I think he can't stop that battle, because of that book

Yeah fighting them against there will/consent that is wrong but that is how world works, in Real life too, if you didn't become intelligent World will take advantage of you. That is how world works.

And what if some bad guy or mental ill guy attack kolulu and her family what will she do, cry help! Help! She should stand for herself and fightback at least defend herself. When I saw that scene I cried, but now I know even if you are crying you have to fightback

In battle they didn't chose only king, they chose helper of demons, old demons and baby demons who can't defend themselves. Like Kanchome is crybaby but if he sees a baby demon is in danger he will help him without doubt and even brago, bari, and I guess gorm too since he is friend of kanchome and he might have told gorm to help weaks