The Tekur Queen was too strong to handle alone. Her relentless attacks were strong and precise enough to kill multiple enemies simultaneously, but only if their defenses were too weak. Some of the Divine Subordinates were struck to death with a single blow, but beings like Mekhaz survived much more.
Mekhaz used Living Armor, Energy Absorption, Repel, and his other Soultraits such as Gigantification, Taunting Grimace, and One Man Army to throw himself against the Tekur Queen.
One Many Army worked well enough because the number of Tekur in the background was only slowly decreasing. There were still more than enough enemies in One Man Army's range to push Mekhaz's power level up a notch. If not for that and his Last Rope Soultrait, Survival King, Mekhaz would have difficulties surviving one blow against the Tekur Queen, let alone a barrage of whip-like lashes.
