Sigmund is an antagonist in the MMORPG Runescape and a worshipper of Saradomin. He is a member of the H.A.M. cult, a group dedicated to removing monsters from Gielinor. He attempts to completely wipe out the Dorgeshuun goblins during their quest line on several occasions, who in contrast to the other goblins in the game are a peaceful and intelligent race.
In the first quest in the series, Sigmund steals Duke Horacio's silverware that had been passed throughout generations, hoping to force him to declare war against the Dorgeshuun. After the player retrieves it, he is fired by the Duke.
In the second quest in the series, Sigmund attempts to flood the Dorgeshuun capital using a drilling machine and murders and tortures Zanik (the hero of the other Dorgeshuun goblins), forcing the player to try to resurrect her. He manages to escape using a Ring of Life.
In the third quest in the series, Sigmund captures Zanik and ties her to train tracks, hoping to start a war between the goblins and the dwarves. The player defeats him and forces him into retreat once again, and saves Zanik in time.
In the last quest in the series, he leaves H.A.M due to disagreements with their leader, and creates a splinter group. He proceeds to capture Grubfoot (a goblin that had been trying to escape his warlike village) and tortures him out of information that he could use against the Dorgeshuun.
Grubfoot is freed by the hero and his base is invaded, causing him to fight the player in a final battle. After the battle is over, Sigmund attempts to retreat using the Ring of Life once more, but Zanik chops off his hand, preventing him from escaping. Zanik (who has become possessed by Bandos) proceeds to murder Sigmund using his crossbow, putting an end to his plans of goblin genocide.
He and King Lathas are the only human characters in Runescape to be considered purely evil. Incidentally, both of them eventually chose to attempt genocide.