Vampire Mastered

Acquire 11 vampire perks - i.e. fill out the Vampire Lord perk tree (a Dawnguard feature). Become a Vampire Lord (side with Harkon, or have Serana turn you), then feed on victims as a Vampire Lord to earn perk points and spend 11 in the tree. You can be a werewolf too across a save, so this doesn't lock out Werewolf Mastered - just do them at different times.