Bastian Wolfe is Time-Rider's biggest foe! Wolfe was Adolf Hitler's right hand man during World War II, and has gained access to time travel in a never ending pursuit to bring back the Third Reich to power.
Bastian wears a mask to hide injuries received during time travel. Even though he finds nothing morally wrong with murdering or stealing to promote his agenda, he finds lying an intolerable character flaw. He has similar skills akin to Time-Rider. He is a master at hand to hand combat and an expert marksman.
Bastian's shocking orgin was completely revealed in The Time Cruisers Exodus Trap. This is the T-Zero time line version of Bastian. Also Bastian's horrible childhood experience was revealed in the short story Bastian Wolfe - the Origin of Time-Rider's Greatest Foe