Van Kleiss is Rex's arch-ememy. He thinks Providence is not to be trusted and he wants EVOs to live. He even thinks that Rex should not trust Caesar. Dispite the way he looks, he is probally 50 or 45, at least to around that age. When Rex sees him, he wants to do what any hero would do to get rid of any villian.
depending on what the information he gave. He probally knew Violeta and Raefel, for at least when she was young and probally spied on her kids.(Caesar and Rex.)