Blood Pact of Cania

Heroic Tier
Prerequisite: Tiefling, Cha 13, warlock, Infernal Pact class feature
Benefit: You gain a +2 bonus to damage rolls with any warlock power that uses Constitution for attack rolls. The bonus increases to +3 at 11th level and +4 at 21st level.

Published in Player's Handbook Races: Tiefling, page(s) 25.