Claymore- the whole premise of the show is Clare and the other Claymores fighting demons called Yoma. There is a good amount of blood and some swearing, but it's a great anime that I loved!!! And I'm surprised nobody said Soul Eater, where the characters have to battle demons called 'kishin eggs' and witches, and the main bad guy is actually a Kishin.. It's awesome. There is a LOT of swearing, more in the sub than in the dub, but even the dub has alot of swearing. But the whole premise is amazing, the thought of two souls resonating as one soul... I LOVED this anime, and it doesn't hurt that the soundtrack is addicting, either!