I Reincarnated as a Support Character with an S-Rank Harem, So What?

A programmer endlessly exploited by his company. Before the launch of their most ambitious game, he decided to get revenge by adding a secret skill: Debt. A mandatory order that heroines had to fulfill every time the support character helped them. The company found out. They punished him. And he died of exhaustion before he could delete it. But he woke up inside the game. "Wait... the Debt skill is still active!" Now he's a Rank B support character surrounded by Rank S heroines... and every time he helps them, they owe him something. What to expect: Character progression / Harem / R18 / Fantasy / Demon Lords / Worldbuilding / Multiple races / Fantastic creatures / Magic / LitRPG elements / No NTR.