Hematophage

Hematophage is a Fallout 3 perk. It cannot be taken on level-up, but can only be gained through the Blood Ties quest.

Blood Packs heal 20 Hit Points instead of 1 point.

Obtaining
To obtain this perk, convince Vance to enter into a deal with the town of Arefu by passing a Speech check, a Medicine skill check, or an Intelligence check at the conclusion of the Blood Ties quest. Then return to Vance and ask to be shown the ways of the vampire.