He didn't see it coming; didn't realize anything till that moment had passed. Large amounts of dust and debris had been kicked up in the sheer destruction they had caused within the kekkai. A few sakura petals too were mixed in, floating harmlessly about despite their use as weapons just moments before. Subaru could see the Sakurazukamori's figure only vaguely as particles of rubble continued their descent to the ground.
Subaru was off-guard. That was the opportunity Seishirou wanted, and the both of them knew it. The silhouette disappeared, darting off into some random direction. Subaru's eyes scanned the clouds of dust for some sign of a tall man in with a billowing coat. It only took a second for Subaru to whirl around and find his predator coming quickly for him.
He didn't fight it. As the other man closed in, Subaru saw his arm raise into its killing position. The Sakurazukamori's hand was poised to stab through his slender body, destroying him in a storm of flower petals like his sister. It was honestly a bit hard to imagine that a hand would be able to pierce anything instead of buckling under the strength of bone, but he knew better than to question the effectiveness of the technique.
Seishirou reached striking distance. He wore that smile he always had, innocent and charming, although in reality the man rarely fit that description. Subaru berated himself for years for allowing himself to be tricked by it. The man was not a kind-hearted veternarian; he was a lying killer. But Subaru fell so hard for the lie. Some days he even tried to convince himself that he could be content if the other man reconstructed that facade right now. It would be like the days of the bet, just...without his sister. Sometimes he thought he could be satisfied like that, but most of the time he knew Hokuto's murder would continue to haunt his memories.
Subaru didn't know whether to keep his eyes open or shut them tight for the blow. It seemed morbid to observe his own death, especially when he knew it was coming. His ponderings, however, never reached a conclusion. In that instant, Subaru felt something take him over. He wasn't in control of himself for one brief moment. He couldn't think, couldn't understand what was going on. All he knew was that something compelled his left hand to mimic the movements of it's counterpart's. But then it moved faster.
He'd understand later that that something turned out to be fate.
He heard people calling his name, but it didn't process. He didn't even recognize the voices. All he saw was his left hand covered in blood. It withdrew itself when Seishirou fell to the ground, red pools all over their clothes and the bridge. It was a distinctly gross sensation, feeling his hand move through the body. Both their breaths were shaking slightly; his from horror and the Sakurazukamori's from struggling to hold on.
Subaru gripped the other man tightly with the very hand he had used to kill him, still dyed crimson and dripping. It seemed so grotesque and even blasphemous, but he just couldn't let go.