D&Dtools1

A luminous ring of holy power appears above the head of a good creature and remains in place until the spell expires or the creature is slain (reduced to -10 hp).
If the latter event occurs, the halo discharges an arc of divine energy that deals 1d6 points of damage per caster level (maximum 20d6) to the target's slayer.
The creature subject to the attack can make a Reflex save to reduce the damage by half.
Once the vengeance halo unleashes its energy, it disappears and the spell ends.
Abstinence Component: You must abstain from alcohol for 1 week prior to casting this spell.