Brisingr (3.5e Feat)
From D&D Wiki
The ancient pact between elves and dragons in the name of peace has been a devoted cause of all Dragon Knights since the beginning of The Blood Ceremony in which Dragons were recognized as an intelligent sentient being of magnificence that could lend aid to the wellbeing of Toril.
Prerequisite: Human, Half-Elf, Wood-Elf, High-Elf; restricted to using Bastard Sword, Two-Bladed Sword, and Longsword,Dragon Knight, Variant
Benefit: Whenever the word "Brisingr" is uttered, the blade of the Dragon Knight's choice will burst with cold blue flames, being able to deal damage to incorporeal/ethereal creatures, and gaining the ability "Smite Evil" as a cleric would.
Normal: the smite ability of a Dragon Knight's blade can be accessed 3/per day + Dragon Knight's Wisdom Modifier.
Special: The cold blue fire on the Dragon Knight's blade is treated as Faerie Fire and is only harmful to Undead.