Venompool is an alternate reality version of Deadpool from Earth-90211. He is the combination of Deadpool and the Venom symbiote. Being part of Earth-90211 he is a part of a reality the Beyonder loves partying in, a reality perpetually stuck in the 1980's in many regards, Venompool is the Beyonder's go to party-animal, until the party got boring for the Beyonder.
As a multi-dimensional version of Deadpool, Venompool is considered a member of the Deadpool Corps simply by existing. Venompool was among the Deadpool Corps seen in Deadpool Kills Deadpool #2. He later is seen as one of Evil Deadpool's Evil Deadpool Corps. He is presumably killed shortly after this point, but that is unkown. His appearance changed rather drastically in the time between What If? Venom Possessed Deadpool #1 and Deadpool Kills Deadpool #2, in his initial appearance, Venompool looked like a cross between Venom, Deadpool, and Rick James, in his recent appearances, he mainly resembles Deadpool with Venom's mouth.