You have accidentally transmigrated in your favorite novel, being in the mc's body you have no choice but to act like like nothing happened

Although, Thirteen, originally a powerful villainess with a Reaper's blood becomes slowly obsessed of you when in fact she was supposed to despise you and be a fake friend towards you just like how the story goes.

"Tsk. Why would you buy one when you can buy all?" Her tone is playful, the two of you were in the store supposedly buying clothes