Although he managed to land a hit here and there, blasting some black-horned demons, and even a Tauren to pieces; Atar was getting tired. He got hit and grazed by different spells and attacks, not only draining his stamina but also wounding him slowly. Luckily, the World Tree spell was continuously supplying him with vitality and mana. Without it, this fight would be way harder, and Atar probably wouldn't be able to walk out of it without severe injuries.
He had no idea about the strength of his opponents before he rushed in, he was just worried about his mom. If he knew they were this troublesome, he would've thought about his attack a little more instead of just blindly rushing in by himself.
