My reason (soukoku au)

"If I say 'Don't leave me ', will you stay?" His voice sounds awfully sad even though he tried to hide it.

Chuuya turned to make eye contact with Dazai. Giving him a cold glare. "I thought you were smart enough to know the answer." He smirked then turned back and left Dazai behind at his office alone.

"Right... Not after what I've done. Right, Odasaku?"

Note: This is soukoku reverse au fanfic. Dazai was Port Mafia's boss while Chuuya were armed detective agency's member.