Kai has never appreciated the fact that he had no one to go home to at night, no one worrying about him staying out too late or whether he's getting enough sleep or whether he's doing something as basic as brushing his teeth or eating—until now.

He's only a couple months from graduating high school yet he skips classes. Miwa leaves him fifty texts a day asking where he is, is he okay, our homework in economics is… but he ignores them. There's guilt there, of course—Miwa genuinely cares for him and his well-being, and he's an asshole to ignore that—but it can't be worse than the guilt that boils up inside of him when he's reminded that everything that happened with Link Joker was entirely his fault.

The hot guilt wrenches at his insides when he goes to see Aichi, sleeping on that throne for eternity, damned to a life of non-existence because of Kai's selfishness, Kai's arrogance, Kai's pride. It keeps him awake at night. It keeps him from eating, tells him he doesn't deserve even that much for what he did.

He listens to it, because it's right.

Ishida hasn't played Vanguard since Kai failed to save Aichi. Neither has Kai, but he doesn't deserve the comfort that playing Vanguard used to bring him. Ishida does; after all, it was Vanguard that gave Ishida the first friends he had ever known, it was Vanguard that put a smile on Ishida's face. Kai knows Ishida resents him, even if he says he doesn't, and it's one more thing Kai has to feel guilty over.

If you lose… you will become my new Quatre Knights. You will watch over me for eternity.

It was a gamble Kai took because he was so sure he would win; in his pride and arrogance, he had given up not only his own life, but Ren's, and Leon's, and Ishida's.

At first, he couldn't bring himself to go to the sanctuary. He didn't want to see Aichi's motionless body sitting out of reach behind a field of energy Kai couldn't break through. Part of him was tempted to pull a Serra and fight the others so he could break the barrier and go to Aichi, to touch him, to hear his voice, just to know he was alive.

Ren had seemed to know this was Kai's plan. He had just smiled.

I absolutely will not fight you.

After a while, he spent all of his time there, sitting for hours in silence as he watched Aichi. Sometimes he would talk, knowing that no one was there to hear him.

You gave me a love for Vanguard I'd never had before. And this is how I repaid you. It should be me sitting there, it should be me that everyone has forgotten. A world without Kai Toshiki is a world that keeps turning. A world without Sendou Aichi is a world that has lost the sun.

Aichi never responds when Kai speaks, and that's fine because Kai doesn't deserve to hear his voice again.

Leon visits him at the sanctuary one day.

"There's a storm here," he says simply, standing with his hands behind his back and his eyes fixed on the back of Aichi's chair. "The wind is destructive."

Kai is tempted to make a bitingly sarcastic remark about how there is no atmosphere on the moon, but he keeps his mouth shut.

"The wind is, of course, yours," Leon continues, and his gaze switches to Kai. Looking into Leon's eyes is like staring into the deepest parts of the ocean, so Kai looks away.

"That's why I'm here," Kai says shortly, "to prevent my wind from doing any more damage."

"Is that what this is?" Leon sounds skeptical. "I was under the impression that you were hiding here to trap yourself in the past."

"I hurt too many people."

"I see." Leon approaches the seals and runs his fingers over the one he is bound to protect. It sparks at his touch. "So Aichi takes your burdens on his soul in order to give you the chance to rebuild your own life and you reject his selfless atonement? You are selfish, Kai Toshiki."

The words sting.

"He did this so you could live in peace."

Kai contemplates this for a moment. He thinks about a time he had stared at the night sky with Aichi, opening himself up in a way he had never done with anyone else. "You… didn't know Aichi the way I did. He filled a void in my life that I had never been able to fill. He was—he is literally part of me. All of his power couldn't make me forget about him."

If I'd never met you, I never would have thought there was anything wrong with being alone.

"I see," Leon says again. "I saw it in your Royal Paladin deck, you know. When you tried to carry on Aichi's will." He taps Kai's seal and Kai feels a jolt run through his body. He doesn't know if it's because of what Leon says or if it's his body reacting to the seal being disturbed. "The deck is a reflection of the fighter's soul. You thought that what he needed from you was to use his deck, to reflect his soul. But it held you back, because what you truly needed—what he truly needed from you—was to follow your own."

Kai hadn't thought of this.

"Aichi's soul spoke to you because you shared one of the greatest bonds two fighters could share. You changed each other for the better. In many ways…" Leon trailed off, staring at the back of Aichi's throne. His violet eyes softened. "In many ways, I truly believe you were soulmates."

All of Kai's self-control shatters at these words. His shoulders shake uncontrollably as the burning tears slip from his eyes. It wasn't fair; Aichi had promised he wasn't on that rooftop to say goodbye to him. He had pleaded with Kai to imagine their future together, with Aichi at his side. He had walked Kai home from Card Capital the night before he left, had held his hand, had given Kai an awkward hug around the waist because he was shorter than Kai and it was easier for Kai to return an equally awkward hug around Aichi's shoulders.

Leon watches him cry, pity in his expression; the humiliation of it only makes the tears fall hotter and faster.

"Imagine," Leon says as he turns to leave. "If you hurt this much over losing him, how much more must he hurt knowing that you have rejected the sacrifice he made for you?"

"How?" Kai chokes out the word. Leon looks back at him. "How could I ever… ever forget Sendou Aichi?"

Leon contemplates the question for a long moment. "Don't forget him, Kai Toshiki. Carry him with you forever." He places a hand on his chest. "He's here. Remember that nothing you did to him is beyond his capacity for forgiveness. Go to school. Get sleep. Play Vanguard with friends. If you truly love him… then live. That, I think, would give him peace."