Frosthorn executioners and nightgores are triggered spawns - after clearing the packs of Frosthorn shadowgores/stormcallers/vindicators from around ( 115, 24, -542 ) Copy/waypoint 115, 24, -542 and ( -10, 23, -438 ) Copy/waypoint -10, 23, -438, a group of executioners and nightgores will spawn. Killing the southern bunch of executioners/nightgores has a chance to spawn Bron Frosthorn, the northern bunch has a chance to spawn Bloodrage.