MC is a bird (yaozu) who fell in the magic mirror who experience countless virtual worlds and awakened his phoenix blood in the process. In a particular vampire world he met a player who told about the rules of the horror world. After clearing that world he found himself in the body of a fool who originally had S grade physique. He had a suitor who fell in love with his beauty but after knowing he's a fool felt ashamed and bullied him together with his cousin(?). MC decided to act as a fool and live as a salted fish. The player he saved is from a wealthy and gave him money, smart brain and snacks. ML is a general(?). He is a sentinel whose spirit body is an Indus tree (the tree that phoenixes like). The horror game is actually made by the demon in the mirror to collect energy and even stole ML's core. MC and ML eventually returned to MC's world and was welcomed by the whole yaozu.
Do you remember if you read it on NU or somewhere else? Translated or raws? It sounds a little bit familiar, but I'm not sure.