Manga by author Kyuugou - Status ongoing

In a city where the law has been rendered non-existent, Yuki and his best friend Tetsu break into the offices of the Seidoukai to steal in a desperate attempt to finance his ailing brother's hospital bills. They ultimately fail but instead spark the interest of the mob's young leader, Kazutaka Hyodo, who offers Yuki a deal he can't refuse: pay him a visit at his office once a week and all hospital bills will be taken care of. Yuki accepts without hesitation and in order to keep his end of the deal, starts paying Hyodo the visits he asked for...

Daichi's big sister is getting married, and to a super hot guy named Jun Igawa! When they first meet, Daichi's suspicious; what does this accomplished, rich, attractive guy see in his sister? But Jun seems like such a nice guy, and slowly, Daichi starts to drop his guard... is Jun really everything he seems? Or is he a devil in disguise?