He should've known. Purely because you were that calm, that infuriatingly unreadable, and outrageously strong enough to be his equal. Fatigued and panting. Bloodied and kneeling beside his split body, seconds from death. An accepted peace in your eyes as you exhaled with a stubborn decision you had made. One that made him, who was already about to die, widen his eyes.

Gojo Satoru was loved by many. But never enough to pull something as ridiculous as trading lives. As ridiculous as making a binding vow that was too severe. But there you were. Feelings given up on years before this predicament. Never acted on.

Satoru knew and yet he couldn't do or say anything about it. It'd complicate whatever friendship that had been built, and since you didn't seek to confess or seek an answer, he simply never gave one. And as the years passed, the friendship was there but strained. You'd work with him, still bicker with him and be annoyed with him. But when the world got quiet, you didn't look at him anymore. Your eyes bagged from a greater acknowledgement that there was nothing there. Somehow worse than before.

But it was fine. It was bearable. Because both of you were still partners. Roommates. Friends. Equals. The strongest.

So when he lost, when his body got split apart and he hallucinated dead friends, Gojo Satoru was at peace. At the very least, despite his regrets, it'd all be okay.

Until in his blurred but still sharp input from the last of his Six Eyes caught the flash of cursed energy in your fatigued eyes.

A secret binding vow you had once talked about. Determined to never use it because it meant throwing your life away. The life you fought hard everyday to carve. You swore to never use that ability.

Yet here you were. Summoning the vow on a man that never told you he loved you. On a man that upon the verge of death was healing as part of you started to rot away. A man that was terrified of a life without you and realised what he actually felt too late.