After the death of Nod's father, Ronin become his mentor and looks out for Nod where-ever he can. Nod realise that Ronin plays an important part in his life at the end of the movie.
Ronin is a strong minded and a very brave warrior, he will fight and even sacrefice himself to save the world.
Ronin is voiced by Colin Farrell.
Ronin used to be strict and serious throughout the movie, until the end when the spirit of Queen Tarra showed up, he now is a very happy character and shows his emotion.