Sigdis Gauldurson is one of the more powerful opponents met during the quest Forbidden Legend.
He was one of the three sons from the Gauldur family killed and expunged from the history books in the quest "Forbidden Legend". He took part in killing his father, Archmage Gauldur, and holds one third of the amulet that he and his brothers stole and split.
Sigdis is a very powerful draugr. He carries the Gauldur Blackbow, which absorbs level-dependent amount of points of magicka per hit. He also knows the Unrelenting Force and Disarm shouts, and he teleports when he has been hit a few times, as well as creating clones of himself to trick opponents into wasting their attacks. An easy way to tell which is the real Sigdis is to target them. The real Sigdis will show damage if he has been injured, whereas the clones will always have full health. Alternatively, in the first battle Sigdis will not glow as much as the clones, while in the second battle he will wear a different helmet from them. When dead, he will have the Gauldur Blackbow, a Gauldur Amulet Fragment (stamina version), and a Writ of Sealing, along with some arrows and sometimes minor loot. As he and his clones use Unrelenting Force frequently, it is hard to use melee attacks. Followers help in fighting the clones and detecting the real Sigdis. The real Sigdis (not the clone) wears an Ancient Nord Helmet, whereas the clones wear the same helmet as Jyrik and Mikrul Gauldurson.
- Sigdis's surname is a common Scandinavian patronymic (Gauldurson = Gauldur's son).
- If Sigdis is killed by the damage from a damage over time effect (from weapon enchantments or the Flames spell), or the real Sigdis (that is, not his clones) is finished off with a finishing move, OR from being backstabbed from sneak, just before he teleports away, his corpse disappears, unable to be looted. May be fixed by exiting Geirmund's Hall and re-entering, with his corpse now laying under the quest marker.
- If Unrelenting Force is used on him just as he teleports, he will reappear laying down, impervious to all melee and ranged damage. Magic attacks will still injure him. Using Unrelenting Force again will fix this.