I really wish Marie would come back as the body of a servant or even a Marie-Face.
Like Saint Olga just for namesake jokes.
Her soul's stuck in Shiva. so untill they can get that back and somehow pulled her out of her unending torment, she won't come back. and honestly I hope she does because she doesn't deserve to have her soul burned to ash for *eternity.*
Do they require a body for a Servant? I'm pretty sure a significant portion of the current list of Servants had their living bodies horribly mangled, so logically Olga should still be able to become a servant even if her body was destroyed in the explosion.
Regardless I 100% support Olga Servant (wasn't she supposed to be a really good mage aside from having zero potential as a Master? Caster Olga-Marie please DW). Maybe revive Lev again so she can beat the snot out of him for her debut fight.