Mark of Avernus

(Fiendish Codex II: Tyrants of the Nine Hells, page 84, DnD 3.5)

[General]

Your unfailing allegiance to Bel gives you special strategic insights into the best ways to overcome your enemies. By examining your opponents, you can land telling blows.

Prerequisite

Brand of the Nine Hells, allegiance to Bel

Benefit

You are a master strategist. Once per encounter, you can make a single ranged attack, melee attack, or use one of your spell-like abilities as an immediate action. In addition, whenever you successfully hit an opponent with an attack made as part of a readied action, you gain a +4 bonus on your attack roll and damage roll, and you automatically confi rm a critical threat on such an attack.