Perhaps if I had some of Serah Kerrigan's DNA from after she was cured of the zerg and then became one again. The Xel Naga wouldn't have control over her DNA... I don't think. Having some kind of clone from her would be interesting because she had some crazy ass powers. Especially when she was a human because she trained with high templar or whatever. I can't recall how that worked but yeah. Also most of the abilities from the Protoss are advanced tech. It was the reason that the Xel Naga made the zerg... supposedly. So the character would be a Human/zerg Hybrid with some tech from the protoss... maybe.