you have a very useful demon art. you can send people back into the past or future

it's currently almost midnight, the final battle is happening. every single demon slayer is trying to kill all the upper ranks and muzan. while you're working your ass off, sending demons back in time a few hours or even minutes so they're back to not dying

while the demon slayers look seriously pissed off, not knowing which demon is helping. everyone's trying to kill muzan, but multiple have died by now