Although if a war of attrition was conducted, perhaps Zhou Tian could still win. However, who could know that if things were dragged out too long, that NPC force might achieve a breakthrough from the pressure they were under. If Zhou Tian's Beastmen not only failed to take down those NPCs but instead allowed them the luck of a breakthrough in strength, and they ended up possessing greater power, wouldn't that be a case of outsmarting oneself?
Therefore, because NPC evolution rules differ, in Zhou Tian's eyes, if he really faced them head-on, the best method would be to destroy them outright from the start. Otherwise, if he couldn't destroy those NPCs all at once, it would be better not to take action against them at all to avoid the NPCs becoming stronger the more they fought.