I see people complaining that the heros are too naive and just end up on the right place due to plot armor or whatever, but that's not the way I see things. The way I see it, it's Ares who is on the wrong, manipulating (or attempting to) everyone around him to achieve his goal no matter the cost, including torturing a creature twice, even worse the second time after he confirmed that she's capable of comprehending human language and speaking.
What would have changed if Ares had told the truth from the beginning to the hero? The truth about his high level, the truth about Toudou's low level in comparison to the monsters he wanted to fight, the truth about him not wanting to take on the job? Would he have been expelled from the party? Toudou seems to have a serious fear of men, but Ares never tried to see past that even after being prompted with Toudou's reactions. He just assumes the worst and rolls with it.
Toudou's group is not on the wrong here - they do not have all the information they need to understand the severity of the situation. Ares does, however, he refuses to share with them. Toudou was really smart in kicking him out of the party because, if he sensed Ares was hiding so much from him, then how could he trust the priest with his life during combat? And what about the night, when he'll be sleeping and vulnerable to whatever Ares must be plotting?
The way I see this story is Ares being an idiot by letting a group of kids run to their doom because he can't see others as anything but a nuisance.