The eastern overlord versus Skoll is something that can only be stated as not fair. The eastern overlord with his two subordinates is battling Skoll with Solstice, Lycan, and the beastkin warriors. The eastern overlord might have been winning but there are many beastkins that are already dead on their side.
The beastkins are now half the number that they have. Some died while some got critically injured and are no longer able to battle. Even with Levin Cloud's support, they could not et back to battle as the attacks of the unique boss is preventing healing effects.
Everyone damaged by Skoll will get the reduced healing status debuff due to her skill Cauterize. The heat of her attacks basically immediately burns the wounds thereby immediately closing it. The closed wounds would then slow down in healing as it is still burning their skin layer.