This is a story I've always wanted to write because outside of Pyra, Nia, and Mythra, Praxis and Theory are my favorite rare blades because they have a very interesting backstory. Unfortunately, I totally forgot about them until after I beat the game. While the quests for both blades aren't really postgame quests, since I completed them after I beat the game, my mind is wanting to set this in the post-game world.

Also, as this story isn't about Rex, let's just assume that postgame, Pyra and Mythra are combined back into one Blade despite the ending credits. You can read my other story, The Aegis' Edge, if you want to know what I think about Rex's relationships. So here we go, enjoy!

"Theory! Theory!" Praxis cried as she saw the ice Blade fade away and return to her core crystal.

She fell to her knees as she picked up the inactive core crystal. Nia put her hand on Praxis' shoulder, unsure of what to say to make the situation better. Of course, the Encourager in Chief found words to say.

"Cheer up, Praxis. We'll wake her up as soon as that crystal lights up. Why don't you keep that crystal on you and let us know when it's ready?" Rex said.

"Oh…I'll make sure to guard it well," Praxis replied.

The group, Nia, Rex, and Zeke, was in Temperantia, disposing of the infamous core crystal hunter crime ring. After the death of the ringleader, they obtained Theory's core crystal.

It began to thunder in Temperantia, and the crew decided to hurry back to port and take the ship back to Leftheria. Pandoria used her Electric Mastery as a lightning rod so the crew wouldn't be struck as they darted back up the mountains and towards the port.

"Oh that feels great," she said as she received a dose of lightning. The lightbulbs on her head began to glow.

To prevent Pandoria from becoming overloaded with power, Zeke used Overloaded Thunder Beam on random objects.

Praxis always seemed impressed at how the crew always worked together through difficulties. It wasn't until after Rex saved the world that she became a Blade for Nia, but the group still stuck together, solving problems for others in Alrest.

Pyra, sensing that Praxis was in distress decided to walk with her. Praxis walked with her head down, still staring at the core crystal in her hand.

"Hello Praxis," Pyra greeted with a warm smile.

Praxis looked up at Pyra and smiled. She appreciated Pyra's concern greatly. Pyra always took care of everyone, whether it was Rex or someone else in the crew. Praxis knew she was an Aegis, the most powerful Blade in existence, but Pyra was always sweet and gentle.

"Hey, Pyra," Praxis replied.

"Is everything alright?"

Praxis wanted to lie to avoid keeping Pyra for too long, but Pyra wasn't so easily deceived. Praxis didn't say anything for a while so Pyra held out her hand.

"Come on, let's go onto the ship. We can talk there," Pyra suggested.

"It's okay, I don't want to keep you for—" Praxis began.

"Girl, she wants to talk to you and make you feel better, why don't you just do it?!" Mythra said suddenly, before immediately switching back to Pyra.

"Oops, sorry," Pyra said, laughing nervously.

"It's okay; I would like to have a chat."

The crew boarded the ship, and Zeke closed the hatch.

"Are you sure you closed it fully, Shellhead? Last time you closed the hatch, an Ansel got into the ship," Nia teased.

"Hey! That Ansel was a gift from the Architect for our dinner!" Zeke replied.

"Yeah, thanks to Pyra who can make anything taste good."

"Why thank you," Pyra said, blushing slightly.

Pyra nodded at Praxis.

"Hey, Nia, could I borrow Praxis for a bit?"

Nia turned towards Pyra and nodded.

"Yeah sure."

"On second thought, since you're her Driver, you may want to join in on this," Pyra suggested.

"Right, if you'll excuse me Shellhead," Nia said.

The three girls disappeared into a room, leaving Rex with Zeke, Pandoria, Turters, and Dromarch. Dromarch was taking a nap though.

"So I can only assume there's some girly talk there right?" Zeke asked.

"I don't know Zeke; I think they may just be trying to cheer Praxis up. You know she feels like she's Theory's sister."

"It's my fault, I shouldn't have told her about her past," Rex commented.

"Don't be ridiculous, chum! I think she appreciates you telling her about her past. Blades often long to know what they were like before. It gives them personality," Zeke replied.

"I don't know if Praxis wants to remember that she was part of a criminal group though."

"Wait, you told her that, chum? You should have only told her the good parts."

"That's kind of hard to do you know. I only knew Praxis when she was that criminal's Blade."

"I see, well I think things will be better once that core crystal is active again. One of us can resonate with the crystal and bring Theory back to life."

"You may be right, Zeke."

"Could you tell me about my past again?" Praxis asked.

Pyra and Nia stared at each other as if wishing the first person that blinked would explain Praxis' troubled past to her. Nia lost that one and she began to tell Praxis about her history.

"Well, your master wasn't such an upstanding person. He stole core crystals from others and did a lot of harm. That doesn't mean you were a bad Blade; you were just doing what your Driver wanted you to do. You and Theory were both very close to each other though. So, I guess she was devastated when we obtained your core crystal too. You two saw each other as sisters though. I never forgot that" Nia said.

"You were pretty quiet though, and Theory was more outgoing," Pyra noted.

"I see," Praxis began. "I guess I will try to be more outgoing this time around. I just hope the new Theory will like me as a sister."

"We'll do whatever we can to help!" Pyra said.

"Yeah, don't worry about it!" Nia added.

Praxis cracked a smile. "Alright, I guess you guys aren't so bad, much better than my previous Drivers."

The three girls came out of their room and saw that Zeke had decided to take a nap on the couch. Rex and Pandoria appeared to be playing some card game on the dining table. It didn't seem particularly fun with only two people, so Pyra, Praxis, and Nia all decided they wanted the Rex to deal them into the game.

On the cards were pictures of various common Blades and the objective was to quickly play a more powerful Blade on top of an existing Blade before someone else plays one. Pyra was a natural at this game. As an Aegis, she knew the stats of all the common Blades without needing to look at the cards except maybe a quick glance.

Surprisingly, Mythra interrupted Pyra's thoughts.

"Let Praxis win a few times," Mythra said to Pyra.

"Since when did you start acting considerately?" Pyra replied in her thoughts.

"Since now."

After a few rounds of the game, Zeke woke up, disturbed by the noise. He then complained there wasn't much to eat on the ship.

"Haven't you eaten enough, Shellhead?" Nia asked, folding her arms.

"I'll go make dinner," Pyra said.

"Do you need any help?" Rex asked.

Pyra smiled at Rex. Rex wasn't particularly skilled at cooking, and he was quite clumsy at any task Pyra would give him. He almost lost a finger the last time he handled a kitchen knife.

"I'll be fine Rex, don't you worry," Pyra said, giving him a quick kiss on the cheek.

"I'll help! I can wash the vegetables," Praxis said.

"That would be great, Praxis!" Pyra said.

"I would slice things too, but that's a bit risky with one eye."

"Why do you have that eyepatch on?" Nia asked.

"The world isn't ready for The Eye of Shining Justice!" Praxis said proudly.

"Shellhead! What have you done to my new Blade?!"

"No! She's infringing on my copyrights! Why is her eyepatch cooler?"

"Praxis isn't you, Shellhead," Nia retorted.

As they joked around, Theory's core crystal began to glow. This caught Praxis' attention, and she picked up the crystal.

"Who should resonate with this crystal?" Praxis asked.

Rex, Zeke, and Nia looked at each other for a moment. Zeke wouldn't always be around, so that eliminated him. Praxis would like to be with Theory more often. Between Rex and Nia, Rex gestured toward Nia.

"I think you should do it. They are practically sisters, and it would be nice if they could be around each other all the time," said Rex.

Nia nodded at Rex and picked up the core crystal. Nia was surrounded by a white light, and a few moments later, Theory stood before them.

"I swear by this sword! I will cleave all! I will protect all!" Theory said. She acknowledged Nia as her Driver.

"Hello, sister!" Praxis said.

"Sister, and who do you think you are? Calling me sister?" Theory sneered at Praxis.

The words stung Praxis.

"W-what?! Theory! We were sisters in our past. We did everything together!" Praxis pleaded.

"What if I don't want to be like my past? Just leave me alone!"

"Praxis…" Pyra began. "Let's give her some time alone. Hopefully, she comes around soon."

"You come right back here, Theory!" Nia shouted.

The Blade turned to look at her Driver.

"Yes?"

"Praxis just wants to be friends. Why don't you give it a chance?"

"Hmph!" Theory said before walking away.

"My lady, it appears you have two Blades that don't get along well."

"Thanks Dromarch for stating the obvious!" Nia yelled.

As the mood was distinctly dampened, most of the gup left the kitchen leaving Pyra and Praxis alone.

"Do you get along with Mythra?" Praxis asked.

"Most of the time we do."

"You see her as a sister right?"

"Pretty much."

"Do you ever fight with her? She's pretty feisty."

Pyra switched to Mythra.

"What did you say, Praxis?" Mythra said. Mythra laughed as she saw fear in Praxis' eyes.

"I'm just messing with you, girl. Pyra and I have our differences, despite us being from the same core. I argue with her sometimes, but we don't have a choice, but to get along. We do it for ourselves, and we also do it for Rex."

Mythra switched back to Pyra.

"If we fought all the time, Rex would have difficulties. We needed to be above that."

"Didn't Mythra create you though? Surely she could have created an agreeable sister right?"

Mythra appeared again. "Where's the fun in that? I'm about to let you in on a secret, Praxis. Don't you dare tell Rex!"

"Yes, Mythra. I won't."

"I never was fond of my abrasive attitude, but that's just who I am. When I created Pyra, she was in impression of who I wanted to be. In the end, I created a sister whom I love dearly."

Pyra returned.

"The point is we aren't perfect sisters, and we fight too. You shouldn't be discouraged because Theory doesn't like you now. She's new to the group and has no memories. Some Blades don't respond well to that. Let her affinity and trust in us increase a little before trying to make friends with her again. I know it's not easy."

"You two never lost your memories though."

"Sometimes we wish we did, but Rex showed us differently. I think we should help Theory form new memories about you. Maybe one day, she will see you as a sister too. It'll take time."

"Thanks, Pyra and Mythra. That makes me feel better."

Praxis soon finished washing the vegetables and was helping Pyra watch over the food, making sure things didn't burn. The group ate dinner, but there wasn't much talking. Theory did not seem particularly interested in chatting.

"Theory, how's the food?" Pyra asked.

"It's fine," Theory said.

"Are you sure? You barely ate anything."

"I'm not that hungry."

"Come on, Theory. You should eat," Nia insisted.

"Fine, I'll eat," Theory said.

Theory did, in fact, like the food that Pyra made. She just wasn't particularly talkative, and she didn't smile at all. Once dinner passed, Nia told Theory that she was going to have to share a room with Praxis. Nia, Pyra, and Rex currently shared a room together as Rex was actively in a romantic relationship with the two girls, but the room did not have any more room for Praxis and Theory.

"Only if she does not call me 'sister,'" Theory said.

Nia looked at Praxis and gave her a pleading look.

"Sorry, Praxis," she said.

"It's fine. I guess it'll be just like having Dromarch in the room, except I can talk to Dromarch."

"Dromarch, could you make sure they don't get in a fight?"

"Certainly, my lady."

Theory and Praxis did not say a word to each other the whole night which made the peacekeeping efforts uneventful.

"Good morning, Theory," Praxis said.

"Morning…" muttered Theory.

"Did you sleep well, Theory?"

"I don't know…I was whatever..."

The ship had docked into Fonsett, and the group was making their way to Aunt Corinne's for breakfast. While they were on their way, a Quietus Aspid cut them off, itching for a fight. Rex invited Mythra to fight alongside him.

"Just don't lose focus, Rex," she said, nodding at him.

"Rolling smash!"

Meanwhile, Nia decided to use Praxis and Theory for most of the fight to try out some new combos.

However, this was not going as well as she hoped.

"You are in my way!" Theory complained.

"Oops, sorry!"

"Vulture Peck!"

"Scorpion tail!"

"Ice Slash!"

Nia was waiting for Praxis to be able to use Geyser Spring. Theory was supposed to be their tank but appeared to be taking more damage.

"What are you doing Praxis, I'm taking damage!" Theory shouted.

"Sorry! I'm waiting for Geyser Spring! We need healing!"

"Anchor shot!" Rex shouted immediately.

They gathered the potions quickly and got some healing. However, it was too late, and they had to restart the combo.

"Overloaded Thunder Beam!"

"Ice Slash!"

Theory again started taking more damage and blamed Praxis. Nia tried to stop them, but her health was critical. Rex didn't have another Anchor Shot ready in time.

"Dromarch!" Nia shouted. "Healing H-"

The Aspid hit Nia with its tail, and she was down.

"I-I can still fight…"

But she couldn't.

"Sacred Arrow!"

Mythra and Rex were able to get the Aspid's health low enough that Zeke could finish it off with an Ultra Lightning Fury Slash.

"Nia! Nia!" Rex shouted.

"My lady!" Dromarch rushed to Nia's side.

Nia looked up at Rex and Dromarch.

"I-I'm sorta okay," she said, smiling weakly.

Rex put Nia on Dromarch, and they walked to the house.

"It was your fault, Praxis!"

"How was it my fault? You kept taking a lot more damage. Why didn't you ask for healing sooner?!"

"If you could only get your arts off faster!"

"I was trying my best! Why do you hate me, Theory?!"

"You two, shut up!" Mythra shouted. "Your Driver is hurt. Why don't you worry about her? You need to work as a team next time. We could die otherwise!"

Rex and Zeke looked at Mythra, half-afraid that she might vent at them. She didn't though. She walked back next to Rex and held out her hand. Rex took it, and they walked together. Rex looked worryingly at Nia as well. She appeared to look comfortable on Dromarch's back and waved to let them know she was still fine.

"It's just a bad bruise," she said. "Just a little shaken up."

Praxis and Theory hung their heads after the telling off they received from the Aegis. They didn't bother to look at anyone.

"Good heavens! What happened?" Corinne said.

"We botched a battle with an Aspid a little bit. She just needs some rest," Mythra told Corinne.

"Oh, you should be more careful."

"Yeah, we just underestimated it. You know, typical recklessness from Rex."

Mythra winked at Rex to indicate that she didn't want to tell Corinne the real reason.

"It was my bad. Sorry guys," Rex said.

Praxis appeared shocked that Rex was taking the fall for Theory and her mistake.

"Don't worry about it," Rex whispered.

But she was worried. Did she let her Driver down? She watched as Dromarch took Nia to a room to allow her to use Healing Halo on herself in hopes that it would lessen her pain.

"Can I come in?" Praxis asked Nia and Dromarch.

"My lady?"

Nia nodded. "Sure."

"I'm sorry Nia, I let you down."

"You did not."

"I've done a combo with Dromarch before. I don't know what happened to me."

"Sometimes combos just don't work out."

"But this was different; I had Theory shouting at me too."

"I know, it wasn't pretty. I still think you two will eventually be friends. It might take more work though. Maybe we should have a do-over with a weaker enemy and work our way up. The more you work with Theory, the more she'll trust you. Let's give it a shot."

"Sure. Theory! Oh, Theory!"

Praxis poked her head out of the room to find Theory was missing and Rex staring at an open door.

"She left on her own. I tried to stop her, but she just ran away," Rex said frantically.

"We couldn't stop her," Pyra said.

"Theory…" Praxis said, trying not to cry.

Where could Theory have gone? Without her Driver, Theory would be vulnerable. Praxis couldn't bear the loss of her sister Blade again. She sat down in a chair and buried her face in her hands.

Pyra sat down next to her.

"Praxis, Theory'll be back. She's probably taking this loss really hard," Pyra said.

"How do you know?" Praxis asked.

"Leftheria's not very big; there's only so many places she could hide. I think she's just not used to us."

"She's nearby," Nia said. "I can sense it as her Driver."

"Should we go look for her?" Praxis asked.

"Of course we should," Rex interrupted. "I'm not losing Theory! Let's go, guys!"

Rex had the usual fire in eyes when he was determined to do something.

"Hold it! Don't you think you should let my lady rest a bit?" Dromarch said.

"Right, let's take a break first," Rex agreed. "Praxis, I promise you we'll find your sister!"

I'll be traveling for a bit so the next chapter will most certainly be delayed.

I decided to write this after doing all of the quests involving Theory and Praxis. I don't think they easily accepted each other as sisters right away. Blades lose their memories. Theory can't possibly just accept Praxis as her de facto sister right away, especially when their personalities are nearly opposite of each other.