Unbound Master
From Tardis Wiki, the free Doctor Who reference
This version of the Master spent time on an alternate Earth where the Doctor did not get exiled in the 1970s, this Master spent his time stuck on Earth through the 70s right through to the 1997 when the Doctor is sent to Earth by the Time Lords. He regenerates when he crashes an experimental plane on Hong Kong, he was working under the name Ke Le. (DWU: Sympathy for the Devil).
