Boznitz was the leader of the Graxnix.
In the 41st century, he and the Graxnix invaded Earth, burning London to the ground. They followed the Tenth Doctor through a chronal interface to 2008. They wanted to obtain the Chronexus 3000, which Majenta Pryce gave to them. However, the Doctor had altered it so when they returned to the 41st century, they were trapped outside history, unable to affect anything. Boznitz begged for mercy, but the Doctor told him that this was being merciful. (COMIC: Hotel Historia)