Tobi was one of the Koga ninja dog, who lived in the 1570-1580's.
Ginga Densetsu Akame
Later, Tobi and Ryōga arrive to the village, where Tahei and Kuma are. Their intent is to verify that there are no sign of Kuma or Iga ninja dog. However, Tobi and Ryōga, Tahei smell of people and detect Kuma.