Brothertale
A/N: the creative juices are running hot, so I've gotta keep this going. Unfortunately, Alexus isn't exactly in any shape to be doing much of anything, so things will be a little different this time. Here is Chapter 7: Deal with a Flowery Devil.
Darkness clung around me, coming and going every few seconds as slow snippets of sound and sensation made their way to my weak awareness. I was barely able to hear, and what I did didn't make a whole lot of sense.
'...don't know...heal...degree...damage'
'there must...you can do...'
'if you...won't hurt...promise.'
'...because...helped...'
'...owe him...'
Eventually, trying to decipher even these small snippets was too much, and the darkness claimed everything.
(Somewhere else, through someone else's eyes...)
A lone girl ran through a fiery landscape, ignoring the two side paths available to her entirely, instead heading for a large metallic building, the word 'LAB' emblazoned on it. The girl paused for just a moment before entering.
"Hello? Is anyone..." The girl trailed off as she caught sight of a strange yellow lizard type monster in a lab coat, eyes glued to a monitor just to the left of the entrance, with two figures battling on the screen.
"Is that...Alexus!? You're watching them fight?"
"Er...yes. H-h-hiya, I'm Dr. Alphys. I'm the Royal Scientist. I-it's n-nice to m-meet y-you." Alphys said, a nervous tremor visibly affecting her.
"A pleasure to meet you. My name is Frisk. So why are you watching my brother fight Undyne?" Frisk said.
"That's your brother? Does that m-mean..."
"Alphys, I've known since Snowdin that someone has been watching me. You don't need to pretend like you don't know who and what I am."
"...umm...ok..."
"Well, since I'm reasonably safe here from being attacked, I guess I may as well watch my brother fight. Unless you want to try and take my SOUL from me as well?"
"N-no, I'm not m-much of a f-fighter."
"Well that's good, because I don't really want to fight you either. So watching the fight together it is?"
"Sounds good." Alphys answered. Frisk turned to face the screen.
I believe in you Alexus...but it would be better to be safe than sorry.
*Watching this battle on the monitor...fills you with DETERMINATION.*
FILE SAVED.
Almost absentmindedly, Frisk reached out and SAVED, before really beginning to pay attention. Alexus's SOUL had been turned green, and her frantically defended using the shield that mode gave him. Frisk stifled a gasp as he took a hit in the back.
"Be more careful brother..." Frisk said quietly, as even more attacks closed in on him. Finally, one spear slammed into his back, almost exactly where the other one had. Instead of shrugging it off, however, he spasmed and fell to the ground.
"Ooh, that looks like it hurt. Doesn't look like he's getting up." Alphys said, seeming to forget who else was watching. Frisk frowned.
*LOAD*
"Ooh, he dodged it, just barely. Careful Undyne! That looks like it hurt. But that spear from the side...ouch." Alphys said, fist pumping as Undyne wound up a kill-blow.
*LOAD*
"Whoa, how is he reacting so fast. WOW! He actually grabbed her spear out of midair. But Undyne won't fall for that. Oh no, Undyne is...whoa! I didn't think she'd set an awesome trap like that. But that poor human...OW!
"ALEXUS!" Frisk shouted almost involuntarily as she watched Alexus charge forward, only to be skewered by a massive spear. Undyne claimed his SOUL triumphantly.
No way! As many times as it takes...I'll guide you through this Alexus.
*LOAD*
"SO CLOSE! Undyne, you almost got him!"
"Could you remember who else is watching Alphys! That is my brother out there, and I'd appreciate it if you didn't act like him getting hurt is a good thing...at least, not in front of me!"
"Er...I-I'm sorry. I f-forgot."
"...It's fine. I guess Alexus won anyways, Undyne won't be able to keep going in that state. Hopefully he has more luck sparing her than I did." Frisk said, turning away for a moment.
"...you should keep watching." Alphys said seriously, as the room lit up with light from the monitor.
"Why, he alrea..." Frisk trailed off as the camera was able to deliver a clear image again.
"SO COOL! How did she do that!?" Alphys squealed, looking at Undynes new form. Frisk, however, could only stare in mute horror.
That's...Undyne the Undying!? But I didn't...
Frisk trailed off, the thought cut off before she finished.
Oh god...Alexus...What do I do? How do I prevent this!?
Frisk grew pale as she realized the truth.
There's nothing I can do at all! Alexus...run away! You aren't a match for her like that. Neither of us are.
Frisk's horror at the situation only grew as she watched Alexus fight for his life, desperately using items to try and keep his HP up...only for him to fall to Undyne's relentless attack.
I have no choice. Keep trying, as many times as it takes.
*LOAD failed*
What!? Does someone...have more determination than me!? But who? And WHY NOW!?
Frisk was broken out of her panicked thoughts by the sight of Alexus suddenly bolting upright, and forcing himself to his feet.
Wha...Alexus! You're ok!
"I don't know how your survived that, but you can barely stand. I'll make it quick." Undyne's voice sounded through the speaker. Frisk was completely floored by what she heard next.
"This pain...it's like nothing I've ever felt before...I can barely see...everything is going dark...I feel cold...All I want to do is lie down and let myself die...but there's something holding me back. A promise I made to someone I care about. My precious younger sister. Frisk. The one you fought and tried so hard to harm.
I fought my way here, making sure I kept my hands clean, so I could look her in the eyes when I found her. To tell her she is still loved, even if our parents abandoned us. To tell her she still has a place in this world. That whatever reason she had for climbing Mt. Ebbot wasn't enough to make me abandon her.
But you're standing in my way. You want her SOUL. You want to kill her.
But I WON'T let you do that.
NO MATTER WHAT HAPPENS. I WILL PROTECT THE ONLY REAL FAMILY I HAVE LEFT. AND IF YOU REFUSE TO GET OUT OF MY WAY...I, ALEXUS, WILL STRIKE YOU DOWN!"
"Whoa...that's...hey, are you crying."
Frisk raised her arm to her eyes, trying to slow the sudden flood of tears.
"Are you ok?"
"...I'm fine. He...that was..." Frisk couldn't describe the warmth that spread through her after hearing that. She also couldn't tear her eyes away as Alexus proceeded to turn the tables on Undyne.
"HNGH...WHY!? Why are you growing even stronger as the battle goes on. JUST WHAT ARE YOU!?" Undyne's voice echoed through the lab.
"I'm Alexus! And this power...is my DETERMINATION, to defeat YOU!" Alexus answered. Frisk's eyes widened in shock.
It's...you? Your DETERMINATION...overpowered mine?
Frisk shook her head, clearing her thoughts, watching helplessly as Undyne threw out all the stops trying to defeat Alexus.
She's going even crazier than...those times. How is Alexus surviving this? How is UNDYNE surviving this!?
"I gave that attack...everything I had...how are you...still...alive..."
"Because I'm fighting not for myself, but for my sister. I'd fight my way back from hell itself to protect her."
"...I suppose, if I must die...I'd rather it be against someone like you. Make it quick."
"...I want to. I really do want to kill you. You threatened my sister, you actually succeeded in killing me once, and you are likely the strongest threat in the Underground."
Alexus!? I thought you'd changed. Why are you...
"Then do it!"
"But there is one thing holding me back. My sister would not want me to. I'm sure if I did, and explained my reasoning...she'd eventually forgive me. But...I don't think I could forgive myself. You are just trying to help your people...people who were sealed away by my ancestors. Sure, I refuse to accept the blame for what they did...but if I refuse to help you now, I become as bad as they were. So...because of that..."
...I shouldn't have doubted you Alexus.
Frisk thoughts again wandered to the dark parts of her past.
Hehehe...you've surpassed me, even if you don't know it. You would never respect me again if you knew...
Frisk watched as Alexus gave Undyne a Crab Apple, and couldn't help but smile despite her quickly darkening mood.
And after this, Undyne shouldn't try and kill him, her honor won't allow it. It should be relatively easy to...
Frisk's train of thought was broken as Alexus suddenly collapsed to the ground.
WHAT!?
"What just happened!? Why did he..."
"He's hurt. You see it all the time in anime, where the hero just barely wins a fight, then collapses due to injury. But is this like Dynamo Star, where he actually dies, or like 'Lion of the West', where the hero survives?"
"This isn't an anime Alphys! This is REAL!" Frisk shouted angrily, as she moved to leave.
*The thought of SAVING your brother fills you with DETERMINATION.*
FILE SAVED.
At least I've got my SAVE power back under my control.
"W-where are you g-going?" Alphys asked as Frisk opened the door.
"Waterfall! I have to try and help him."
"But..." Alphys was suddenly interrupted by her phone ringing.
"Huh, who could that be?" Alphys asked.
"It's...Undyne!" Frisk said, pointing at the monitor, where sure enough, Undyne was holding a phone to her ear.
"O-o-oh. I-I c-couldn't p-possibly..." Alphys seemed to grow even more nervous.
Normally I'd play along with her crush, but I don't have time for this right now!
"Then give it here!" Frisk snapped, snatching the phone from her.
"Alphys?" Undyne said.
"Alphys is too scared of her own feelings to answer the phone. What are you trying to do Undyne?" Frisk said, controlling her voice to not give away her emotions.
"What did you do to her human!" Undyne shouted.
"Nothing! I'm not the type to hurt people. You should realize that much, you beat me half to death without me throwing a single punch in retaliation."
"...whatever! What can you do about injuries to a human?"
"...Not a whole lot, especially with what you've done to my brother."
"What do you mean!?"
"I can see you right now on the camera monitor. Alphys was watching the battle, so I watched too."
"...so what do I do? I don't know how to heal that degree of damage."
"And you think I do?"
"Surely there must be something you can do for him!"
"...maybe...but how do I know you won't just attack me. This could be a trap!"
"If you come, I won't hurt you. I promise."
"Why are you trying so hard to help him. You're trying to get a human SOUL, right? Isn't this a perfect opportunity!? What's your goal here?"
"...I'm helping him because he helped me."
"That doesn't seem like a very strong reason."
"I don't want to owe him anything! He saved me, don't think I don't realize that I was about to die before he forced me to accept that apple. I owe him a life-debt. But once he's healed...all bets are off. But...I won't harm you, since it was his only request."
"That sounds more like you. Alright...listen to me. Carry him somewhere safe, your house would likely be best. Start boiling cloth for bandages and for god's sake, don't overdo it and burn your house down. I'll be on my way with Alphys, and hopefully I'll have everything I need to give him a fighting chance."
"Alright."
"One other thing. Don't you dare let him die, Undyne."Frisk said, suddenly calm. However, Undyne got a shiver down her spine, as she felt that despite the calm demeanor and lack of anything indicating it, what she had just heard was a threat.
"...I understand."
"Good. Goodbye Undyne." Frisk said, before ending the call.
"Alphys, I need you to gather some supplies before we leave. I need syringe needles, a plastic bag for holding liquids, and tubing, and it all needs to be sterile. If you have a small shunt that would also be helpful, but if not I'll work without it.
"What are you doing?"
"Alexus lost a lot of blood. I'm going to give him some of mine."
"I...er...admittedly don't know a lot about human biology, but isn't it bad for the wrong type of blood to be given to someone?"
"Yes, but I know something you don't. My blood type is O-, also known as the universal donor. I may not know what Alexus's blood type is, but it doesn't matter, since mine will work. Most of the other types of complications won't be an issue because we're siblings. Also...if you have any kind of sugary drinks, bring those too."
"Why?"
"My body will need fuel to replace the blood I'm going to give him."
"But isn't that really dangerous?"
"I'm willing to take that risk."
After all...I get as many chances as I need to get this right. And I'm sure I'll need a lot. But...I won't let you die like this Alexus!
The two of them spent less than 10 minutes gathering the needed supplies before setting off for Waterfall.
Frisk threw open Undyne's house door and stepped inside without a moments hesitation. Undyne and Alexus were both present, Alexus still unconscious and Undyne doing her best to comply with Frisk's requests. A pot filled with water and cloth boiled on the stove, which was running at a reasonable heat.
"Move." Frisk said to Undyne, taking her place sitting next to Alexus and peeling away the blood soaked clothes from his body carefully, cutting away what was necessary with a knife quickly taken from Undyne's kitchen, which was sharp enough for this. She winced as she saw the extent of the damage.
*The thought of fixing this fills you with DETERMINATION.*
File SAVED.
"You're acting pretty different than you were before. Showing your true colors?" Undyne said.
"Maybe. Or maybe I'm pretty upset because someone stabbed my brother a dozen or so times, and I'm putting on a strong face so I don't break down crying!" Frisk said, her voice growing steadily louder until it was just short of a shout. Undyne had the decency to at least look a little ashamed, averting her gaze. Frisk turned back to Alexus.
"How are you even still alive..." Frisk muttered. She then smiled, as she seemed to realize.
"Of course...you always keep your promises to me. Undyne! Get me some of those cloths, and boil more water."
"Wait a minute, you can't just give orders..."
"If you have a problem with it, save it until I've pulled my brother back from death's door! And if you're not going to help, then leave, since you'll only be in my way!" Frisk shouted. Undyne took an involuntary step back from the angry girl. Despite how easily she had nearly killed the girl earlier, every instinct Undyne possessed screamed that the girl was dangerous. Undyne shook her head before complying with Frisk's demands. Frisk turned back to dressing her brother's wounds and bandaging them as best she could.
"Alphys, prep the needles and blood bags."
"What the heck is a blood?" Undyne said.
"Blood for humans is basically what magic is for monsters. We need it to live, and any injury that breaks the skin results in us losing some of it. Lose too much, and we die...though that isn't the only way we can be killed. We can also share blood if needed, but there are a lot of conditions that need to be met, which I do." Frisk explained, as she rolled her sleeve up and tied a tube around her arm.
This is it. No matter how many times it takes...I'm going to save you.
"I'm going to drain some of my blood into this bag Alphys. I probably won't be in any condition to do anything once it's done, so listen. You need to..." Frisk explained basic first aid to Alphys, as well as her best idea on how to administer the blood to Alexus afterwards.
"...after the bag is filled, you'll need to close the shunt, since I don't exactly feel like bleeding out...do you got all that?" Frisk finished.
"...yeah. What if it doesn't work..."
"Don't worry about that."
It will work...or it won't happen.
It didn't happen, and continued to not happen. Frisk grit her teeth as she once again siphoned her blood into the bag.
The first time, Alphys had been overwhelmed with the situation, failing to properly complete Frisk's orders, and Frisk had awoken hours later to a fearful Alphys and a morose Undyne. In a certain special type of container which Frisk had seen before in other times, was an orange SOUL. Frisk rejected that reality immediately, LOADing without saying a word.
The second time she failed to properly insert the shunt into herself. She never awoke, instead finding herself with the option to LOAD or RESET, without ever having the chance to fix the mistake before bleeding out.
The third time Frisk found that her bandaging job needed work, with Alexus bleeding out despite her efforts. Again, she was presented with an orange SOUL.
And this time...her hand slipped, the blood in the bag quickly spilling. In frustration, she LOADed once more.
WHY! Why...won't this just WORK!
...but I WON'T give up.
Again and again, Frisk continued to meet with failure after failure...until...
"What if it doesn't work..."
"...Don't worry about that." Frisk said wearily.
"Gah...you're awfully stubborn for someone so useless. No matter what you do, he'll die. You lack the needed skills and you know it." A sudden voice entered the conversation. Frisk spun around, trying to find the source.
"I'm in the window, you idiot." Flowey said, as Frisk turned to face him, Knife already in hand.
"What do you want!?" Alphys said, as Frisk moved to a defensive position near Alexus.
"Nothing you can help with. Only she can do what I want...or rather, what I want her to 'not' do. But she won't stop...unless he lives. I can't stop her...so if I want it to stop, then I need to help you save him." Flowey said. Alphys turned back to Frisk, a confused look on her face.
"And what would you even know about this!?" Frisk shouted.
"Ah...we can't have a nice talk about 'that' unless the idiot scientist and fish-bones for brains give us some...privacy." Flowey said, giving them a wide grin. Undyne moved towards the window, preparing to attack, but Frisk held out her hand, stopping her. Frisk glared at the SOULless flower, but slowly lowered her weapon.
"Alright. Alphys, Undyne...please watch over Alexus while I talk with the flower." Frisk said.
"You can't, you don't know about..."
"Flowey was the first thing to attack me in the underground, and nearly killed me. He's been following me ever since. If I give him half a chance he'll do his best to kill me and take my SOUL for himself. I know I can't trust him as far as I can throw him...but he's right. I'm bumbling around here, trying my best to save someone precious to me, but I'm going to fail. I...I have to try."
"But..."
"I've decided! Please Alphys..."
"...ok. Please, be careful."
Frisk nodded, and exited the house, leaving her brother in the care of the two monster women.
Flowey led her away from Undyne's home, checking to make sure they weren't followed. Eventually, they found themselves back at the dump.
"There we are, we're not likely to be overheard here." Flowey said. Frisk scowled, crossing her arms and glaring at the flower.
"What are you doing Flowey? You know killing me or Alexus now is senseless. I won't let it stand.
"Oh, I'm all too aware of that! I can't even let myself relax, with all the RESETing you're doing. Don't you care about how it inconveniences others?"
"Seeing as it's only you...not really." Frisk said, sticking out her tongue.
"You're a disrespectful little brat, aren't you."
"Respect is earned, not given Flowey. Maybe if you actually had an ounce of compassion or empathy I might. But we're wasting time...let's just get to the point. What do you want?"
"What I want is for these endless LOAD's to come to an end. But of course, I know you won't stop...unless he lives, you won't ever give it up, will you. So I guess I have no choice but to help you heal him."
"What would you even know about that? Humans are a lot different than monsters."
"Please, do you think I don't know that? I've read every book that has ever fallen down here during my many resets...including medical encyclopedias. Let me tell you, you humans with your physical bodies are absolutely disgusting. But I can probably ensure he doesn't die...for a price."
"You do realize you have one of those 'physical bodies' too, right?" Frisk said.
"Is that really what you want to talk about right now?" Flowey said, his voice filled with false glee.
"...Fine. What do you want in exchange, since I'm sure you aren't going to do this for free."
"You would be correct. I want one thing...and one thing alone." Flowey said, before his vines erupted from the water. Frisk wasn't able to react in time, and was ensnared, and held directly in front of Flowey, who was using his 'demonic' face. Her SOUL was wrenched from her body, as she was forced into a battle. Friendliness pellets surrounded her SOUL, which was confined to a box the same size as her SOUL, eliminating any movements she could make. The pellets orbited her, and occasionally shot towards her SOUL...but turned blue before they impacted, causing no damage. It did, however, function quite well as intimidation.
Flowey's got you tightly in his grasp.
FIGHT disabled.
Frisk LV 1 20/20 HP
XXX *Act Item Mercy
Check *Struggle
"Somehow...you have the power to utterly ERASE everyone's memories. All of my progress...my memories...you can turn them all to 0, can't you?" Flowey said, his happy voice gone, replaced with a much more menacing growl.
*You struggle pitifully. Nothing happened.*
Frisk continued to try, before finally admitting defeat, going slack in Flowey's grip. She glared up at him, but gave a single nod.
"Fine. Yes, I hold that power. I get rid of all the echoes that normally persist through regular RESET's...including your memories."
"That power is the price. You will NEVER use it again."
Flowey's glancing from side to side.
Frisk LV 1 20/20 HP
XXX *Act Item Mercy
Check *Talk
"Even if I agree to this...what's to stop me from breaking my promise?"
"Trust me...that will not be an option. Now...what is your answer?"
Flowey's grinning at you.
Frisk LV 1 20/20 HP
XXX *Act Item Mercy
Check Talk
*Agree Disagree
"...fine."
"Splendid. I'm glad we had this talk." Flowey said. Without any other cue, the friendliness pellets dissipated and the vines released her, expanding the bullet board back to it's normal size.
Flowey is sparing you.
Frisk LV 1 20/20 HP
Fight Act Item *Mercy
*Spare Flee
*You WON! You got 0 XP and 0 Gold for winning.
"Alright...now to go and make this official." Flowey said, as he led her back to Undyne's house.
"Official?" Frisk questioned.
"Yes, official. There won't be any breaking of this promise."
"And how are you going to do that?"
"I have my ways. By the way...you will need to do one more LOAD to save your brother." Flowey said.
"What? Why!?" She said, as Flowey pushed himself up to the windowsill.
"Because, I can hardly heal him when he's dead." Flowey said, as Alexus's body was surrounded in friendliness pellets, which hit home almost instantly. With Alexus being unconscious, there was no way for him to defend or evade the attack, and his HP being nonexistent meant even the slightest amount of damage was lethal. Both Undyne and Alphys had attempted to intervene, but were far too slow. Alexus's SOUL emerged from his now hole-ridden body, and a single vine ensnared it.
"ALEXUS! Flowey...how could you..." Frisk growled out in anger, her hand already clutching the Knife, and her body dropping into a battle ready stance.
"Oh relax, would you? You can just LOAD anyways, and it's necessary. The fool didn't even realize his own power. Determination is powerful, yes...but not that powerful. Were his injuries solely to his SOUL, yes, he could have overcome them with just Determination. The look on your face tells me you're more than familiar with that. But his body was mangled by Undyne's attacks, which have an element of physicality to them. Come to think of it, most of the Royal Guard has that actually. Food for thought. But we're getting off track. Even as physically injured as he was...he still opposed Undyne after being defeated, restoring his own HP, for a limited time anyways. Even now, until I finished him off, he was surviving with 0 HP. That shouldn't have been possible, and with only Determination, it isn't. But...add magic into the mix, and it's a different story."
"Magic?" Frisk said, tense, yet curious.
"Yes, magic. He had no idea he'd become the first human mage the underground has seen in centuries, and with as powerful and rare an affinity as Oath Magic. His silly promises to you let him channel his magic into upholding them, allowing him to push on, as long as he had the Determination to uphold his words. And since you made him promise not to die...unless his magic was completely overwhelmed or he willingly chose death...he would not die. So now, with this SOUL, I can borrow that power, the power to magically enforce a promise or oath. And the best part is the only way to break this oath afterwards is to destroy his SOUL, something I know you will never do. Now then, make your promise! Or I will sit back and watch him die, again and again, all the while refusing to help you. Maybe I'll even kill you every time you LOAD, so you don't even have the tiny chance of success."
Frisk glared at the flower who now held her brother's SOUL, but growled out her promise.
"In exchange for saving Alexus's life, I will sacrifice the 'True Reset' power I possess. But break this covenant, and my promise becomes null and void, and I will do my utmost to make your life hell."
"...You aren't as big an idiot as you used to be, giving yourself that out. I respect that. I accept your oath, as I have no intention of breaking my half of the bargain." Flowey said. As soon as he said the words, silver threads emerged from Alexus's SOUL, and twined themselves into both Flowey and Frisk. Frisk felt something shatter within herself, and knew her capability to use True Reset had just been lost.
"Now, use that power of yours and LOAD. I'll be along shortly to heal your brother." Flowey said, setting her down somewhat gently.
"...why? Why are you doing this?"
"Just how many RESETs...how many timelines have you lived through...and stolen from me. Growing and learning, but keeping me from maintaining the same. I refuse to allow you to keep that advantage. The game's no fun if one side is too strong, after all. Honestly, I could care less if he lives or dies, but you care, which is what matters here." Flowey said.
"And how did you figure out that I had this power?" Frisk said, changing the subject.
"...small inconsistencies. Like I've said, I've read everything there is to read down here. Psychology is another one of the things I studied...and you don't act at all like the child you should be. I can see the experience you hold...the fear of the unknown that you lack...as well as the darkness within you try so hard to hide and deny. In the end, you're just like me, so you must have lived through many RESET's already in order to become this way. Once I realized that, I watch and waited, and took the first opportunity I had to deal with it. And now...you've lost that advantage over me."
"...I never considered it an advantage. I'll be happy to see the end of that power. I'll see you later Flowey." Frisk said, as time began to shift around them.
Moments later, Frisk was back in Undyne's house, Alexus laying in front of her, alive once more.
"You're acting pretty different than you were before. Showing your true colors?" Undyne said once again. Frisk sighed.
"Just start boiling cloths Undyne, I don't have time to deal with you sniping at me." Frisk said, as she prepped Alexus for Flowey's arrival.
I just hope this deal with the devil is worth it. At least he didn't ask for my SOUL.
...
After all...I made my choice regarding that a long time ago. Isn't that right Chara?
Indeed.
A/N: In my original outline of this story...this was not an entire chapter. This was supposed to take up about 1000, maybe 1500 words worth of story, letting us advance more quickly. But, as often happens when I write, things just keep happening between characters, and suddenly I have a full chapter written on something that's 3 lines long in my outline. Meh, what're you gonna do?
This chapter is the first that explicitly mentions something that is majorly important to the story...the fact that it's a Post-Genocide timeline. It's important enough that I wanted to specifically mention it here, just in case you skimmed over the relevant lines that imply/reveal it. I also revealed that Chara is present and able to speak with Frisk, should they choose to do so.
Secondly, I wish to warn you, what I'm about to write below contains a little information unique to the Brothertale AU that hasn't been revealed to the characters yet, but is relevant to what was revealed. I'll give you the chance to choose to read it now, or wait for chapter 8 first.
Ok, for everyone still here...regarding Alexus gaining magic. If you feel this is completely out of left field, I ask you to re-read Chapter 6(if you reach the Undyne fight you've gone too far).
According to that set of glyphs, humans having magic at some point is CANON, since it took 7 human magicians to create the barrier in the first place, which means it is more than possible for someone to awaken the bloodline now. Why now? Well...Alexus has been exposed to magic, a brand new experience for him, so why not let that act as a catalyst for awakening his own latent ability. In any case, it shouldn't cause many problems in terms of story pace. This is not a combat power(at least, in it's current form), and won't interfere with his normal stats barring certain special situations. What this particular magic can do is limited to three main functions.
A) Can temporarily empower himself in the pursuit of fulfilling a promise. Alexus's promise to not die was one such promise, and his power manifested as additional Determination not his own(allowing him to overpower Frisk for a few moments), as well as stalling death for a small time so Frisk has time to attempt to save his life. This power is unique to humans due to the usage of both magic and Determination. Undyne does NOT use this power to become Undyne the Undying, the similarities of the effects of Undyne's Determination and Alexus's magic in this particular case are purely coincidental. This power cannot be invoked intentionally, and attempts to do so will instead cause this power to fail.
B) Can magically enforce a contract/oath/promise, forcing the participants to uphold their part of the bargain to the best of their ability. Thus, making someone promise to not die will cause them to avoid battle and flee from anything dangerous, while forcing someone to promise to die(somehow), would be immediately fatal. Alexus does not yet know enough about magic to consistently use this power successfully, and in fact, is unaware he possesses it as of now. This is the power Flowey used to bind Frisk.
C) If an opponent is weak enough, Alexus can use his magic to force them to stop fighting(impose a promise on them consisting of 'don't attack me anymore'). This is called 'Suppress' in the MERCY menu, as opposed to Spare or Flee. This is the only power Alexus can use freely. Unlike Sparing, it becomes more difficult to Suppress enemies with high LV and AT, as the mistrust and unease caused by them make it more difficult to force a promise on to them.
In terms of overall power, I rank Alexus's power just slightly under Frisk's in terms of usefulness, and completely fitting with Alexus's personality.
