Set'alahd Crool was a member of the mage cadre of one of the Holy Protectors in Seven Cities. He was a Jhag half-blood who had once managed to drive back Dassem Ultor a half-dozen steps with a sword which had been ablaze with the blessing of an unknown Ascendant.
During a rebellion which had originated in Aren, the unnamed city had been besieged by Malazan forces. After the Protector was struck down by Dassem Ultor, the mage cabal fled into the Pan'potsun Waste and on into the Holy Desert, Raraku. They were pursued by a cobbled together collection of Malazan forces under the command of Whiskeyjack and guided by a local new recruit of the Claw named Kalam Mekhar. This chase became the event which forged Whiskeyjack's soldiers into the elite Bridgeburner company, so called, because the holy desert was said to have burned the bridges to their pasts.
During the pursuit, one by one, eleven of the mages in the cabal died and shifted their souls into the fittest of them, Quick Ben, and in the end only he remained. Set'alahd Crool was the eight to succumb to the strains of the pursuit.