Viscious

 was a Supermutant commander, who oversaw the operations center in the LA Vault and controlled access to the Master. He had an unhealthy smoking habit, although given the longevity and resilience of mutants, the probability of him developing cancer were slim.

He was killed when the Vault Dweller nuked the Cathedral.

Interactions with the player character
Viscious will attack the player on sight, if he has his weapon drawn, even if he wears Cathedral purple. Otherwise, he might question the presence of the player in the Vault and either direct him to the Master, for a nullifier or attack him.

Appearances
appears in the original Fallout.