Can You Become a Werewolf in The Elder Scrolls IV: Shivering Isles (Xbox 360)?

No. Lycanthropy (werewolf transformation) is exclusive to the base Oblivion game via the “The Witch’s Curse” questline (Hircine’s Daedric quest). The Shivering Isles DLC does not include this mechanic.

Why It’s Absent

• Separate Questline: Werewolf infection is tied to specific NPCs and locations in Cyrodiil (base game).
• DLC Scope: Shivering Isles adds a new realm (Mania/Dementia), main quest, side quests, items, and creatures—but does not port base-game systems like vampirism/lycanthropy curing or contracting.
• No Hircine Presence: The Daedric Prince Hircine (patron of werewolves) has no role in the Isles; Sheogorath (Madness) rules here.

Werewolf-Adjacent Content in Shivering Isles

• Sheogorath’s Influence: Quests involve madness, transformation (e.g., “The Staff of Sheogorath” turns NPCs into animals temporarily), and bestial behavior.
• Creatures: Baliwogs, Grummites, Scalons, Heretics, Zealots—some exhibit wolf-like traits but are distinct Daedra.
• Werewolf Mod: On PC, mods add werewolf form to SI. Not possible on Xbox 360.

If you want to be a werewolf, complete Hircine’s quest in Cyrodiil before entering the Isles. The transformation works in SI if already contracted, but you cannot become one there.