The Mellow Dream.
It's the kind of curse that allows the user to transform their identity into something else totally. For example, you can fake to be a vampire while still being a human.
Though you cannot have the powers of a vampire this way, and you will still be a human.
The reason it is a curse is that it is placed upon someone by another person and cannot be inflicted upon oneself. And there are only two ways to undo it.
One is to die and come back alive like the players did all the time.
As for the other one,
"Mellow dream, huh?" I walked closer to her, wondering what kind of life she had lived.
"You know this curse?" Leena spoke surprised as her eyes locked on to me with a surprise before I asked.
"Can you tell me what are the effects of the curse on you? I know what curse is this… but first I want to know the implications of it on you as it is different for different people."