Ancient Covenant of Nessus
Prerequisite: Tiefling, invoker, Divine Covenant class feature
Benefit: When you use a divine encounter or daily attack power on your turn, instead of your normal covenant manifestation, you can allow one target of the power to make a basic attack as a free action. If the target makes this attack, it takes fire damage equal to 5 + your Intelligence modifier after resolving the attack.
The damage increases to 10 + your Intelligence modifier at 11th level and 15 + your Intelligence modifier at 21st level.
Published in Player's Handbook Races: Tiefling, page(s) 25.