I need help for a concept

So I've been trying to make a concept for William Birkin (The big shoulder with an eye guy from Resident Evil 2) but I can't quite get it. I already have a basic idea of what I want him to have:
So basically, Birkin is able to infect downed Survivors (Similar to what he did to Sherry). Infecting them will grant Birkin Mutation Points (similar to Nemesis). There would probably be a bit more to the infection but I'm too lazy to type. Once he gets enough, he's able to mutate into G2. In G2, he would probably have a Charge Ability that grants him an instadown and a short burst of speed, probably something that has to do with his eye aswell, maybe Killer Instinct on any Survivors within a certain range for like 10 seconds. Problem is, I can't think of a Power that G1 would have. He can't have no Power cuz otherwise he'd be too weak. If anyone knows what would work, I'd gladly accept it, if anyone has better ideas for G2 aswell, that'd be awesome too