Cavall II is a stray dog that is adopted by Artoria Alter during the course of the Shinjuku singularity. He's named after Cavall.

Cavall II is very much loyal to Artoria Alter. He disliked James Moriarty immediately upon meeting him. When Moriarty tried to get him to shake his hand, the dog turned away. When Moriarty tried to give him food, Cavall II smacked the bowl out of his hand.