Boku no Omawarisan
love story between a store owner (ex police officer) and a delinquent that became a police officer later on.
I Wanna Die Before I'm 30
guy gets dumped and is lonely and depressed. hearing his horny neighbors have sex every night makes him even more lonely so he goes and complains but finds out his neighbors are really hawt people. turns out they had some sort of sad backstory where they were abandoned since birth and have grown dependent on each other. but they got bored and wanted to have a person to can both go to which leads to MC. once mc moves on from his ex and finds him in love with his neighbors they disappear and it was revealed they were wanted criminals for stealing millions of dollars from the yakuza and escaped to another country. without a trace mc becomes sad but decides to move on and go back to school. after five years mc becomes a successful businessman and one day when he goes back to his old apartment he finds the two of them back in japan again and they reunite and take him to live with them.
Mobyama Aji to Mobtani Crou no Kareinaru Nichijou e no Chousen