[@Claw2k11]

My suggestion would be making the cursed blood simply a part of your magic rather then a divine blessing, considering that magic in the Re:Zero verse is somewhat ill-defined as it is. His soul stealing is certainly some sort of blessing, for the given amount of blessing such an ability falls under. Though if you do go with my suggestion, you should elaborate more about what your magic could do since it's obviously not like anything seen in either the anime series or light novels (We're trying to keep as close to canon as possible, presence of orcs aside).

That is to say, there's nothing that explicitly says what you want to do is impossible, but there isn't any evidence to support it either.