...but there is tons we could not know about Mihawk...and the WG probably just made him join as a fear thing, not even as an instigator of justice. But, if he did leave WB, then there actually might be a chance he did make a crew, since BB did. Although, BB created a crew to help him become the Kaizagou-Ou, and we don't know if that was ever Mihawk's goal, or if his goal is just to live and find good swordsmen.