Werewolf Mastered

Acquire 11 werewolf perks - fill out the Werewolf perk tree (unlocked via Dawnguard). Become a werewolf through the Companions (Blood Oath), then feed on the corpses of enemies you kill in Beast Form to earn perk points, and spend 11 in the tree. Pairs with Vampire Mastered - you can hold both trees across one playthrough by curing and re-contracting.