Hiromu is a young puppy belonging to Tomon's pack.
Shin Gaiden - Karadaki no Tomon
Hiromu is a little puppy in Tomon's pack. Unlike most young dogs of the pack, he is well-mannered and respects elderly.
He is often bullied and bossed around by Toshi and that's why viewed as his errand boy even though actually Hiromu dislikes Toshi.
Hiromu helps the pack Elder when he feels sick and later curiously goes to see Tomon's fishing. Tomon gives him fish and the puppy explains happily that it is his first time tasting one.
Hiromu is the one who finds the chicken stolen by Toshi and later sees Tomon and Toshi's fight. He is worried when Tomon leaves to the neighbor territory to resolve the conflict, fearing for the old dog's life and the possibility of a war.
He is last seen being very happy when Toshi and Tomon return alive.