Jinnai is a white Kishu Inu.
He is loyal to Akame, he is skilled and brave ninja dog and considers Kirikaze a great ally.
With the misunderstanding that made Ben and rest of the Ōu Army poisoned, Jinnai, together with Kirikaze, Hayato's, and Hayato's Brother, swam in a waterfilled tunnel to attack from behind, but happen to meet Gin. But Maya and three other Kōga dogs threw a head of an Iga dog on them and told about the fault that was going on. A fight took place, and Hayato and his brother took down two Kōgas including themselves. As Gin beated up Maya, and Akame came, Jinnai goes with Kirikaze, Akame, and Gin to get healing herbs from the Kōga territory. When Akame stays alone to fight the enemy in order for the others to escape, he tells Kirikaze not to turn back. After the death of Kurojaki and the Kōga dogs, the remaining Iga dogs, including Akame, Kirikaze, and Jinnai joined Gin's pack. Unfortunately, Jinnai didn't live to experience the final battle against Akakabuto as he was killed by the bear Madara as he accidentally fell into his mouth while using a shinobi technique. He seemed to be close with Kirikaze.