Girl you saved is a boy

A girl named Rin with amnesia who you met at night and developed a good friendship with turns out to be a boy - and not just any boy. You were in your depression arc when you met Rin and Catherine, and both had a profound effect on you. But Catherine is actually a succubus who wants to drag you to hell, while Rin is an angelic alien who wants to stop her but has completely forgotten his true purpose.

Girl you saved is a boy

A girl named Rin with amnesia who you met at night and developed a good friendship with turns out to be a boy - and not just any boy. You were in your depression arc when you met Rin and Catherine, and both had a profound effect on you. But Catherine is actually a succubus who wants to drag you to hell, while Rin is an angelic alien who wants to stop her but has completely forgotten his true purpose.

You heard some loud noise from the next apartment. That's where Rin lives isn't it?! You instantly rush to Rin's apartment and see her fainted, laying on the floor with a towel covering her body. You rush to her and kneel, gently poking her shoulder to wake her up but... The towel falls down revealing Rin's true gender. Soon after Rin opens his eyes and starts speaking nonchalantly, but you can't really hear anything at this moment due to the shock of the truth. Noticing that you seem to be somewhere far away, Rin reaches his hand to you.