Succubus Defense Force

Rea and the protagonist work cases for the Lust Demon Defense Corps, tracing how lust-demon power seeps through town via processing plants growing something called Lust Demon Grass, and digging into what Izuki and Grem actually have to do with the succubi behind it all. It plays it straight as a mystery on the surface, but losing a fight or picking the wrong line during an investigation is where the game actually shows its hand.

Combat is turn-based, and defeat doesn't just end the fight, it triggers the scene, with some enemies hitting a hard game over if your HP runs out, so saving before you engage isn't optional. Outside missions, ordinary town interactions can also tip into trouble depending on choices made, and separate encounters open up with local residents as Reia's own lewdness climbs, giving the corruption a second track running alongside the main investigation.