As Issei predicted, his mother accepted Sona without any fuss. As he introduced his newfound partner of card-hunting to his mother, she instantly took a liking to Sona. However, he did not account for one thing. In their house, there were only three bedrooms. One for his parents, one for him, and one was a spare guest room which got turned into Miyu's room. There was no more spare room for Sona.
In the end, Miyu offered to share her rooms with Sona and she accepted it with no problem. From what he observed, Sona was a highly polite and proper high-class lady who had too many weaknesses that her sister exploited well.
However, Issei thought back to the time he saw her in Serafall's office. If his big sister was a magical girl hardcore fan then he would probably also felt embarrassed by her antics. Serafall, please have mercy on your little sister.
So yeah, all in all, with him saying goodnight to Miyu and Sona, it was a rather good day in his opinion.
Of course, the world had to have a word with him.
Late night, Issei was once again being woken up by Miyu, but this time she wasn't alone as Sona was with her.
When Issei opened his eyes to see the two girls on his bed, he just sighed. "This again? Can't I take a break for one day? Three consecutive days, I tell you. Three consecutive days!"
"It can't be helped, Issei-sama. We detect another Class Card manifestation."
"Yes, yes, oh... I had to guide a complete newbie too. Man, and when I think today is a good day..." Issei muttered as he looked at Sona who was looking at him with a judging gaze.
With grace and poise that eleven years olds shouldn't have, Issei and Miyu snuck out of the Hyoudou household for the third time that week, with Sona following behind them.
With Ruby and Sapphire's guide, they arrived at their destination. a very wide and spacious riverbank.
"Alright, Sapphire, Ruby, try to ease Sona-san a little towards this magical girl business, please," with that, Issei turned his body around and closed his eyes.
"What are you doing, Ise-san?" He could hear Sona's voice asking him.
"Uh, Miyu, you'd better explain."
"Sona-san, a magical girl transformation is sometimes... too revealing. That's why I had Ise closed his eyes and turned his body around."
Sona narrowed her eyes. "But the last time I transformed, it was an instant from normal clothes into the magical girl clothes."
"Ah!" Ruby interjected. "That's because I used the skip button."
Instantly Issei looked at Sapphire. "You shitty explanation device! You never said you have a skip function!"
"Please forgive me Issei-sama. This time I really don't know that we are programmed to do that," was Sapphire's swift reply. "Onee-sama, how to skip the transformation?"
"It's easy, Sapphire-chan! You let our master transform," Ruby let out a bright light, "then force the world to accept that the transformation sequence is complete like this!" not even a second later, the light dissipated and in Sona's place appeared Magical Girl Kaleido Ruby, Sona Sitri edition.
...
"What the hell, Ruby?! 'Forcing the world to accept', since when are you this awesome?!" Issei asked Ruby with a big grin on his face.
"No no no, time out! Time out! What do you mean by 'forcing the world to accept'?!" Sona-ahem, Magical Girl Kaleido Ruby demanded to the stick she held.
Miyu nodded fervently at Sona's question.
"Miyu, I've mentioned this before. Sona-san, maybe you've never heard of this before but magical girls can do anything! Just pour enough level of magic power and bam, anything you need, you will get."
"That's right! Common sense need not apply before the great Ruby-sama!" Ruby smugly declared.
Suddenly there was bright light enveloping Miyu. It seemed that Sapphire was trying to imitate her sister. However, the result was not what Issei quite expected.
For instead of the usual purple outfit that Miyu wore as Kaleido Sapphire, it was a... lack of them instead that greeted him.
Issei blinked.
"I-I-I-I-Ise, don't look!" Stuttering, Miyu covered her almost naked body with her arms.
"A-ah! Right!" Issei shouted in realization. But he did nothing because his mind was still frozen from the sight. It wasn't until Issei felt an unfamiliar warmth covering his eyes that he realized that Sona was the one who prevented him from seeing Miyu's condition further.
"Thank you, Sona-san," Miyu sighed in relief. "Sapphire. How did this happen?"
Complying Miyu's demand, Sapphire gave the full explanation. "Miyu-sama. Please forgive me. It seemed that my attempt to fast forward the transformation sequence to almost nothing failed." Sapphire then transformed Miyu normally into her Kaleido Sapphire outfit. "It is perplexing. I am programmed to be able to do that, yet I failed."
Issei whose eyes were still being covered by Sona clicked his fingers in a breakthrough. "I know!"
Everyone's eyes were turned on him.
"But uh, you know, can you release me if Miyu has finished her transformation?"
Miyu and Sona smiled without Issei's knowledge. After Sona released her hands from Issei's face, Issei began to speak out his theory. "So, it's like this. Miyu, remember what you said last night? You believe you cannot fly because there is no logical mechanism behind a human flying."
Miyu nodded at Issei's explanation, so Issei continued. "But if you remembered, I said there is no need for a mechanism. You just use your gut feeling. Would you understand it?"
"No, I would not."
"The same rule applied to Sapphire's action trying to mirror Ruby. Ruby explained it by 'forcing the world to accept'. But there is no logical mechanism behind 'forcing the world to accept'," Issei made air quotes as he said the words. "You just need to use your guts, isn't that right, Ruby?"
"That's completely right! Issei-san!" Ruby confirmed.
"Even her explanation doesn't make sense. That's because magical girls don't need to make sense!" Issei pointed his finger to Miyu. "Miyu! From now on I don't want to hear scientific and logical things coming out of you! The same also applies to you, Sapphire! When I tell you to fly, just imagine your body being affected by gravity ten times lower than usual or some other things!"
Miyu and Sapphire looked at each other, then looked at Issei.
"What? Come on, just try it!"
"Right now there is a bigger problem than me flying though, Ise. What about the Class Card manifestation we're about to face?" Miyu asked Issei.
"Ah! That's right!" Issei actually forgot the reason why the three of them plus the two magical girl sticks were doing there.
"How can you forget about that, Issei-sama? Shameful."
"You're one to talk, Ms. Oh-I-am-from-another-world-tehee!" Issei sighed. "Whatever. Let's just go, Miyu, Sapphire, Sona-san, Ruby."
"Yes, yes. Starting the dimensional transport!" Ruby shouted.
"Adding imaginary numerical axis to the fifth instrumental variable. Preparing inversion. Confirming the existence of multiple spaces. Fixation of center coordinates complete," Sapphire declared loudly. Issei grabbed Miyu's arm so he could also be transported.
"Forming reflective path with a radius of two meters. Performing partial inversion of Mirror World connections," Ruby continued her sister. As she finished, the world around them was covered in bright light and they appeared in the Mirror World. "Coordinates stable. Dimensional transfer complete."
"...There's something weird I feel. This world... it is not normal," Sona spoke her mind out when she got to feel the Mirror World firsthand.
"I agree, Sona-san. Even though this is our third time here, the feeling never goes away," Issei replied to Sona. "Miyu, what about you?"
"Same. Anyway, Ise. Let's look around for the Heroic Spirit."
"No need, Miyu-sama." Sapphire stopped her. "Look above."
The rest looked above them and saw the night sky is illuminated by countless magic circles in the air.
"...What is that?" Miyu voiced what was on everyone's mind.
"Aren't those..." Sona trailed off.
"Are you fucking kidding meeeeee?!" Just as Issei screamed, the three of them were showered by homing laser beams.
But this was not the end of the magical girls! They survived!
Issei was smirking inside a blue dome formed from Miyu's Kaleidoshield. "Good thing your mind works faster than mine."
"That's not something you can feel proud, Ise," Miyu retorted.
"Anyway Miyu, your enemy is in the air! Make gravity affects your body several times lower!" Issei commanded and Miyu nodded. Her body glowed and then she jumped several meters into the air. "Sona-san, please help Miyu. Whatever magic you can already do, you can do it ten times better using Ruby."
Sona nodded and followed his command despite being older than him. "Miyu-san! You need some way to move while in the air!" She shouted as she flew using her devil wings trying to catch up to Miyu.
Miyu who heard her shout, instantly realized that Sona was right. A laser beam was heading towards her and in the air, she couldn't maneuver out of the way.
"Miyu!"
No. There was a way!
Miyu materialized a shield below her feet and she jumped away using the shield as a platform. Because her body still registered the gravity as six times lower than the usual gravity on earth, her body was flung away farther than she intended. She made another shield and used it as a platform to stop herself and stand in the air.
"Miyu! I'm glad that you are way much smarter than me!"
She didn't appreciate the commentary.
She saw Sona was distracting the Heroic Spirit by maneuvering in the air. Miyu used the breathing room to look at the Class Card she had just gotten last night, the Lancer Class Card.
Should she Install it, or was Include enough? Her mind went back to the discussion about the effect of Installing a Class Card. She was not Issei. She had no container for another soul within her as Issei had. So chances were Installing the Class Card would affect her psyche in the long run.
Her eyes caught the form of Sona being hit by the laser beam.
"Sona-san!" From the ground, Issei was shouting and moving towards her falling body.
She turned her attention back towards the Heroic Spirits who seemed to smirked when her beam hit Sona. Miyu gritted her teeth as she made a decision.
She didn't need to care about the effect of Installing a Class Card now. Right now, her new friend was injured and only she had the power to defeat her, maybe. So there was no other choice. She had to do it.
Ah, Miyu realized. Maybe this was what Issei felt this morning when he said he would do it again. She smiled. Maybe she would apologize to Issei when today's task ended.
Miyu took a deep breath and then put the Class Card on Sapphire. "Install."
Miyu's body was engulfed in bright light. Her outfit changed from her Kaleido Sapphire outfit to blue full-body tights with metal pads protecting her shoulder. On her hands, Sapphire transformed into the red lance that she remembered the Lancer used.
It was... weird, Miyu decided after she finished Installing the Class Card. Just like Issei mentioned, she was still herself. However, she also had knowledge of how to use the lance she gripped tightly. The lance's name was Gae Bolg, the infamous weapon of Cu Chulainn.
But not the Cu Chulainn of this world. She suddenly realized. This was Cu Chulainn of her world.
Miyu turned her attention towards the Heroic Spirit. An unfamiliar smirk adorned her features. She knew how to beat the Heroic Spirit thanks to Lancer's knowledge, and she would do it. She had to.
After exhaling the breath she unconsciously held, Miyu invoked the name of the spear as she channeled all her magic into it, thus unleashing the Noble Phantasm.
"Gae Bolg!" With a single leap towards the Heroic Spirit, Miyu stabbed the Heroic Spirit in the heart.
There were no screams. There were no gasps. The robe-clad Heroic Spirit couldn't say anything before her body disintegrated, with the remaining trace that she had existed was only a single card which Miyu took.
"Class Card Caster," Miyu noted.
She flew down towards Issei and Sona who was still laying on the ground and then Uninstalled the Lancer Class Card. "All done."
"Good work, Miyu!" Issei flashed a thumb up towards her. He then went back to try to nurse Sona. "Where else does it hurt, Sona-san?"
"I...I think my ribs cracked from the fall."
"...That makes it four major injuries, then. I'm sorry, Sona-san, because of me..." Issei was angry at himself.
"Don't feel bad, Ise-san." Sona hissed in pain. "We seemed to forget that your command would not reach us when we fight in the air. Let's just learn from our mistake so it wouldn't be repeated and you can improve yourself, cough!"
"Sona-san!" Miyu approached her new friend. "Because of me..."
"Why are you two so similar?" Sona smiled despite the pain. "I said it's okay. We Devils have sturdier bodies and faster healing. If it's you, then maybe it's more than four major injuries you'd have. More importantly, good job, Miyu-san."
"By the way, why hasn't this world collapse yet? The Class Card is ours. Ruby, Sapphire, do you know anything about this? Sona-san needs help fast. Why don't you transfer us back to our dimension?"
"...I don't know, Issei-sama. We'll transfer all of you, then. Beginning the dimensional transfer procedure..." Before Sapphire finished, Issei felt something bad.
"Miyu! Stop!" Issei moved towards Miyu.
"Ise-san, behind Miyu-san!"
Miyu who was caught unaware because of her exhaustion, only looked back to see a pitch black figure looming over her. Not even a second later, her body was thrown across the river.
"Shit! Shit! Shit! Two Class Card manifestation!" Issei shouted in panic. He was too late to stop the Heroic Spirit clad in dark armor from assaulting Miyu. He hoped that Miyu at least erected her shield to repel the attack.
When the dust settled, Miyu was out cold, her unconscious figure laying on the ground.
"Miyu!"
Issei did not waste any time. He looked at Sona's still unmoving body and groped her from head to toe.
"W-W-What are you doing, Ise-san?!" Flustered, that was all Sona could utter.
"I'm searching for the card holder! Found it!" Inside the cardholder on Sona's waist, Issei found the thing he was searching for, the Archer Class Card.
"...Are you going to do the same thing Miyu-san did, then, Ise-san? From what I can gather, it is the source of personal conflict between you and Miyu-san."
"You mean Install? Yes. I had to. She's unconscious, you're injured. The only one who can do it is me." There was a fire reflected in Issei's eyes, and for the first time, Sona wondered if there was a layer of depth behind the goofy magical girl fan.
"...Then I suppose I could only say 'good luck'."
Issei gave one last smile to her. "Thanks."
He took a step towards the knightly Heroic Spirit with no hesitation.
"Oi, you dark knight wannabe." His taunt seemed to get the attention of the Heroic Spirit. Issei materialized his Boosted Gear and put the Class Card on the green jewel of the Boosted Gear. "How unsightly for an honorable knight to attack someone from behind. Then again, you're hardly an honorable knight, huh?"