When I think about the most badass anime character, Inuyasha comes to mind. Inuyasha is a half dog, half demon who’s purpose is to find the Shikon Jewel. He desires to become a full demon with this jewel. The Shikon Jewel (jewel of four souls) harbors immense power. He has to steal this jewel but it is not easy because it is guarded by a 15 year old girl named Kagome Hirugashi. Kagome is the reincarnation of ancient priest named Kikyo. When Kikyo died,the stone was burned with her body. Precisely, the jewel is inside of her body now.
One day Kagame is attacked and had the jewel ripped from her chest. When this happens, Inuyasha is freed. The jewel breaks into many pieces. Inuyasha and her now have to work together to find the pieces of it before anyone else with ill intent gets to it. Sadly another evil enemy named Naraku is also after the jewel pieces. If he gets his hands on it, he will become the most powerful demon. Now there is a race between Inuyasha and Naraku. Turmoil, fights, deceit and trickery is stirred up from Naraku to outwit Naruto and Kagome.
Not technically a romance anime, but they both team up where Kagame detects where the jewel is and Inuyasha retrieves it fighting. Inuyasha is very strong and is usually fighting off enemies. The power Inuyasha showcases while fighting off enemies is some of the best fighting seen from an anime character. The way he handles his fights and his constant victories is pretty badass. Has to go down as one of my favorite samurai anime. . .well not quite but it takes place in feudal Japan, so close enough.