And on top of all of the complaints already in the thread, WHY do there exist different kinds of werewolves? There are at least a dozen leveled werewolf types, such as "werewolf savage," but we only ever come across them in a couple of Silver Hand cages, where they're alive, stuck, and won't do anything but become hostile if you attempt to free them.
Because it depends on the person's willpower. The Circle have control over their Lycanthropy most likely because of the pact they had done with the Glenmoril Witches. Sinding is like every other werewolf out there, he can transform at will, but he still has lunar transformations, that's why he was so crazy about getting Hircine's Ring.
Werewolves suffer from mental instabilities. They can't sleep well at night, they always have their anger issues at times too. They have the Beast(Or the Spirit of the Wolf) living within them. A seperate entity that causes them to be violent, and more prone to acts of assault or murder. And when that adds to the fact that you turn into a beast twice every month and kill innocent people, it inevitably will lead to insanity. So it's up to the person to enjoy the power, or simply see it as a curse.
All three games have evidence of the Beast or animal within and the toll it takes on the minds of those infected;
Daggerfall:"
You're looking for (family's father)? I'm afraid that he died three years ago. Killed himself, actually, although very few know that part of it. I'm not sure what happened, but he became very moody, and began disappearing for days at a time. Left a note saying something about he couldn't live with himself.""I understand. In fact, I am almost relieved that you shun this road to salvation. It shows that the Beast does not yet wholly dominate you.""
You must be (player's name). (hunter's name) said you might be coming to see me, although (he) doubted that you would heed (his) warning. Sadly, most do not, already too befuddled by the Beast within to save themselves.""He used to be my brother. If you ask me, he died long ago, when he first got bit. He hated himself when he became that beast."Bloodmoon:Werewolf NPC's are named "Ravening lunatic," "Gibbering idiot", or "Insane wanderer". All aspects of mania and lunacy. Most likely they allowed the animal inside to dominate them. Which is why they attack on sight.Skyrim: "Some go feral. Allowing the
animal within to control them."-Aela the Huntress.
"Now I may look like a man, but I still feel
the animal inside of me as strong as ever"-SInding.
"Until we can pursue a true cure, the twins and I have chosen not to
give in to the beastblood. For me, it's provided a clearer head, but Vilkas
seems to be suffering a bit for it."-Kodlak's journal.
"But I still feel the
call of the Blood." Vilkas.