Regos Krang was a Cyberman from the planet Mondas, and the leader of the second Cybermen force which invaded the Snowcap Base in Antarctica in December 1986 with the intention of detonating a Z-Bomb located in its missile silo.
Krang, Jarl and another Cyberman went to try and force their way into the Z-Bomb silo, but were weakened by radiation used by John Dyson and Haines. The weakened Krang was then shot and killed by Ben Jackson. (TV: The Tenth Planet)