Your weapons work in deadly concert to unravel the very essence of your foe and singe its nearby allies.

Daily   ✦     Arcane, Weapon
Standard Action      Melee weapon

Target: One creature

Attack: Strength vs. AC (main weapon and off-hand weapon), two attacks

Hit: 3[W] + Strength modifier damage per attack, and the first attack that hits also deals ongoing 10 damage (save ends).
    If the target is a demon, in addition this damage ignores all resistances, and until the end of this encounter, when the demon takes ongoing damage, its allies within 2 squares take the same amount of damage.

Published in Forgotten Realms Player's Guide, page(s) 58.