The Forsaken One
Explorer
Death Impulse
Necromancy [Death]
Spellcraft DC: 95
Components: none
Casting Time: 1 quickened action
Range: 0 ft.
Area: 20-ft. radius sphere burst centred on you
Duration: Instantaneous
Saving Throw: Fortitude partial
Spell Resistance: Yes
To Develop: Seeds: slay (DC 25). Factors: quickened (+28 DC), no verbal or somatic components (+4DC), change from target to area (+10DC), +10 on caster level to overcome SR (+20DC), increase spell's save DC by +10 (+20DC). Mitigating factors: burn 1200 XP (-12 DC)
As a free action which counts as a quickened spell, you release an impulse of death which slays those near you. All creatures with less than 80 HD who are within 20 feet of you must succeed at a Fortitude saving throw (DC 30+ relevant modifier) or die. You enjoy a +10 bonus to overcome their spell resistance, if applicable.
I guess that was the spell he used on the Glooms summoned by Shomei.