Scarlet the mysterious waif is really Pink the necromancer!It all makes sense, scarlet is a shade of pink and Scarlet used necromancy. Pink's a necromancer, so....
Pink lied about accidentally making a Death KnightWhen Sun comes to her asking about Roland, she claims that she'd only picked up a nice fresh corpse from the execution grounds. She had no way of knowing it had a powerful enough obsession to become a Death Knight. Except that when Sun later reads about the process of making a Death Knight, there turn out to be some pretty deliberate steps required to make one.
Or alternatively, Roland wasnít the true Death KnightIt's just like how Harry Potter wasnít the true horcrux. I mean, come on, he is practically a being made out of darkness yet he was nicer than Grisia. (Although to be fair, being nicer than Grisia isnít that much of an accomplishment.)