Carl is an old terrier from Miyagi.
He refuses to go with Weed's group after being told that they are going to fight Hōgen, knowing he has forces much larger than Weed's group. Carl leaves Weed and had been scaring some other followers that Hōgen's army is ten times as big, making some of them leave as well. He is not mentioned in the story again.
It was Rocket who told Carl that Hōgen has more soldiers than Weed´s group and he leaves along with some soldiers. The next day Rocket tells the group that Carl told him about Hōgen´s army's number.