Erika pushed his head down.
"I am not trying to kiss you."
Akira's head remained under her hand.
"You can, though… Maybe I should have waited until you did it."
She pushed harder.
"Shut up. I am not."
They were still arguing over what exactly she had been trying to do when Selena returned from her research, her telepathic voice sounding tired.
"I'm back…"
She paused, then her tone turned amused.
"Brother, you're looking beautiful. What's the occasion?"
Akira frowned.
"What are you talking about?"
Erika turned her face away.
Selena giggled.
"Look in the mirror. You'll see."
Akira looked around the lab. There was no mirror. Then he remembered his phone, took it out, and opened the front camera.
He screamed.
"EHHHHHHHHH!"
His face was covered in makeup. He looked beautiful. Almost like Selena.
"What the hell is this?!"
Erika kept her face turned away.
"I was just testing my skills, okay?"
Then she acted as if that settled the matter.
"Anyway, as my boyfriend, your face belongs to me. I can do whatever I want with it."
Akira tried to defend his rights.
"That's not fair!"
They were still arguing about boyfriend and girlfriend rights when the large pod on the side of the room opened.
Ritsu's android body rose from inside. She opened her eyes.
"Akira-kun, is there an emergency? I heard screaming—"
She finally noticed his face.
"Oh. Akira-kun looks beautiful. What happened?"
Akira looked annoyed that someone else had seen his beautiful face, but he was more surprised that she had woken up at all.
"Ritsu, you overwrote my code and unlocked yourself. That's impressive. Looks like I'll have to increase the—"
Erika, blushing, pushed him down before he could finish.
"Stop looking at her!"
She sat on top of him and covered his face with her hands.
Then she looked at Ritsu.
"Ritsu. Why are you naked again?"
Ritsu tilted her head.
"Oh, that. I was in my resting pod. It takes care of my body and maintains my E-skin, so my clothes would only get in the way."
Erika was still holding Akira's head down.
"But… but… why did you come out naked just now?"
Ritsu looked confused by the question.
"If I was naked inside the pod, I'd be naked when I came out."
Erika didn't know what to say to that, but she said something anyway.
"I will not allow a naked girl in the lab with Akira… You need a new room, Ritsu. One of your own."
Ritsu tilted her head again.
"Why?"
Her body had always stayed inside the pod whenever she wasn't at school. Her old, stationary artillery body was still in the classroom, and she hadn't really needed a room of her own.
"You're getting one because I said so. Now, go back into the pod. I'll take you to the empty room on the ground floor."
Ritsu tilted her head once more.
"Okay."
She returned to the pod.
Erika looked down at Akira.
"Stay right there."
She picked up the pod and carried it to the room. Only after settling Ritsu in her new room did she return to the lab, where she found Akira exactly where she had left him.
"Good. Now, where were we?"
Akira looked indignant.
"About you putting makeup on my face."
Erika answered as if she were stating one of her fundamental rights.
"As I said, your face belongs to me."
Akira looked at her.
"Does that mean your face belongs to me, too?"
Erika blushed.
"No! That's not how it works!"
They continued arguing.
Selena's voice rang out, now thoroughly annoyed.
"Are you guys just going to ignore me?!"
Only then did they remember Selena and the black gate.
Akira and Erika stopped arguing.
For the sake of the world.
"So, sister. What did you find?"
Selena sighed in their heads.
"Seriously. You two are always so easily distracted."
Her voice turned serious.
"I found some information in the old records in the library. That thing is a gate to the Sea of Nihility."
Erika was the first to react to the name.
"Wait. What thing? And the Sea of Nihility… isn't that the place opposite the Imaginary Tree, where your family's enemies come from?"
Selena paused.
"You didn't tell her about what you saw, brother."
Akira explained, "I don't even know what I saw. I was waiting for you to help me figure it out."
Erika leaned closer to him.
"Explain everything to me properly."
He told her what he had seen when he connected to Kayano's tentacles. The black gate. The cocoon. The eye. He also explained how he had seen the same thing back when he passed out after his heart was destroyed.
Erika listened in silence.
"I'm mad that you didn't tell me immediately. But we can deal with that later. First, Selena. Did you find out what it was?"
Selena's voice turned serious.
"Well, first, let me explain something. There's a form of energy that originates from the Sea of Nihility. When matter and antimatter collide, they produce a tiny amount of energy. And that energy has an extremely faint connection to an ancient energy associated with nothingness."
Akira frowned, focusing on the fundamental problem.
"If it's nothingness, how can anything even form from it? And what kind of energy could possibly exist in nothingness?"
Selena knew it didn't make much sense.
"It's not something created by the Oblivions, if that's what you're thinking. If I had to explain it, I'd say it's something that can induce entropy in other things, gradually reducing them to nothing."
Akira looked even more confused.
"You do realize that makes absolutely no sense thermodynamically, right?"
Selena shushed him.
"Don't question it! I'm trying to explain something that barely makes sense even to me!"
Akira looked up at the ceiling.
"That's not reassuring."
Selena took a deep breath.
"Look. If I had to compare it to something, it would be kind of like Honkai energy. You know, the stuff associated with inducing entropy and breaking things down."
Akira's eyes lit up.
"Ohhh. So it's related to Honkai?"
Erika blinked.
"What's Honkai?"
Akira turned to her.
"I'll tell you… Wait. Did I promise to tell you about it before? I forgot to do that… I'll explain it later today."
Selena cut in.
"You can explain it later. For now, no. It's not exactly the same. It's only vaguely similar. The underlying principles are completely different."
Akira frowned again.
"Then why compare it to Honkai in the first place?"
Her voice rang through their heads.
"BECAUSE I NEED A REFERENCE YOU'LL UNDERSTAND! Let's just call it Super Honkai Energy and be done with it!"
He sighed.
"Fine. We can call it that."
Selena continued.
"Anyway, simply put, when matter and antimatter collide inside the tentacles, the collision produces energy. A tiny fraction of the resulting phenomenon also releases energy with a signature similar to that Super Honkai Energy. Well, their energy signatures are about 0.000000001% similar. And something on the other side forced open a gate to this side."
Erika asked, "Is that even possible?"
Selena sighed.
"No. It shouldn't be possible. There are records from the first war of existence between the Asterians and the Oblivions. Something called a Queen of Oblivion is recorded to have opened gates to new worlds using Super Honkai Energy. But… that was when there was no seal between the Sea of Nihility and the Imaginary Tree. This time, there is a seal. And that energy isn't even that close to Super Honkai Energy."
Her voice turned serious.
"For something to open a gate here, it would need enormous power and a level of computational ability that's nearly impossible to comprehend. Something that could rival your theoretical 100% calculation speed. But even you, in your previous life, never reached that level."
Akira stayed silent.
Something that could match his 100% calculation speed. That wasn't something he could take lightly.
"So, that eye… Is it the Queen of Oblivions? And is she the one who opened the gate? And what does that whole 'Found you' thing mean?"
Selena corrected him at once.
"The Queen of Oblivions, or rather, the first Void Queen, was destroyed at the end of the first war. By the beginning of the second war, the one our family is still fighting in now, a new Void Queen had already been born and was actively fighting against our family… probably. I can't really contact them. But this one… it doesn't look like the Queen from the records. It looks like a cocoon. And its computational abilities are probably even greater than the Queen's. This is something new."
Akira thought it over.
"That… whatever it was… said 'Found you.' In binary. It was definitely binary. Do Oblivions know binary?"
Selena sounded just as uncertain.
"Oblivions don't speak. They're fundamentally different from us, so we can't communicate with them."
Akira frowned.
"Then what is it?"
Selena remained silent for a moment.
"I don't know either. I need more information before I can figure out what it is."
Erika finally spoke.
"Since neither of you knows what to do, focus on the current situation first. What will happen if that black gate opens?"
Selena sighed.
"Well, the situation is dangerous right now. If the gate fully opens, the Oblivions will be able to bypass the seal completely. They could attack not just this world but spread to other worlds, too. And the entire Imaginary Tree would be in danger. We don't have the power to stop them once the gate opens."
Akira asked, "So we just need to destroy the gate, right? Isn't there a way to do that?"
Selena sounded unsure.
"Actually, brother, destroying the gate itself is simple. We just need to hit it with a lot of Stellar Radiance. But… let's just say that whatever it is could probably open another gate in this world. Or maybe even in another world."
He sighed.
"Is there a permanent way to close it?"
She fell silent for a while before answering, her voice firm.
"There is one way. But it's a bit risky."
Erika frowned.
"What do you mean?"
Selena grew serious.
"The records describe a Stellar Radiance technique that can permanently seal off whatever is using that route. But to do that, we have to perform a complex sealing technique with Stellar Radiance at the exact moment when the gate is at its most vulnerable stage. If we do it correctly, we can make sure she can't pull the same trick again for a while."
Akira asked, already suspecting it wouldn't be easy.
"So, what's the catch? It can't be that simple, right?"
Selena went quiet for a moment before explaining seriously.
"The gate will be most vulnerable just before it fully connects to this world. You have to use the technique at exactly the right moment. If you do it too early, it'll be a waste. If you do it too late, the Oblivions will enter this world. And that's not all. Since the tentacles are connected to it, the gateway might be someone connected to the tentacles. Someone with the strongest connection to them, probably. The more the gate opens, the more Super Honkai Energy will pour through it, corrupting that person and turning them into a pseudo-Oblivion, even before the gate fully opens. And that person needs to stay alive while we perform the technique to maintain the connection. Well, if they become a pseudo-Oblivion, they'll die on their own anyway once the gate is closed."
Akira's voice was flat.
"So, we'll have a boss battle against something that can erase data from reality. Something I've never fought before. And we have to keep it alive until the right moment to use some sealing technique."
Selena answered.
"Exactly."
He stared blankly ahead.
"You know that's insane, right?"
Selena replied seriously.
"I know."
He snapped.
"Then how am I supposed to do that in a world where I can't use magic?!"
Selena sighed.
"You can use magic, but… if you want to know, it isn't sealed or anything. It's just restricted by the mission, that's all. But without Stellar Radiance, your magic won't work. And if you use Stellar Radiance, that gate creature will die, so…"
Akira started to speak.
"Then how was I—"
Erika cut in.
"Wait… Just asking, but will Koro-sensei be affected by this? What if he becomes the gate creature?"
Both Akira and Selena fell silent.
Then Akira finally spoke.
"Seems like it's about time we talked to Koro-sensei about us."