A Crossover Harem World, and There Are No Humans Left

After transmigrating into a harem-themed anime crossover world, Amamiya Minato awakens a Regret Value System. He originally planned to capture people's hearts and make them regret rejecting him, but after seeing the lunatics around him, he decides to stop trying to make sense of things. The girl he casually rescues by the roadside turns around and drugs his breakfast; a personality torn apart by love and hate sparks an earth-shaking battle; his "devoted" maid treats him as leverage against her young lady; and a player immersed in a game confuses reality with virtuality and develops an obsessive fixation on him... It's over. There are no humans left in this world.