Kaidos race is not explicitly stated in the One Piece manga or anime. However, there are some theories and hints about his race. Kaido is known to not be a human, which is apparent from his size and his horns. In fact, people like Marco and even Kaido himself have referred to Kaidos kind as Oni. The Oni are a rather mysterious race, as almost nothing is known about them. There are two known members of this race: Kaido and Yamato. Yamato is known as the "Oni Princess," which points toward him being a member of the Oni race. The two of them have one main thing in common, and that is their horns. There is a difference in their heights, as Kaido is much bigger than Yamato. However, it is difficult to guess what other features are unique to the Oni, as there is no other information available regarding this race. Therefore, it is safe to say that Kaidos race is still a mystery in the One Piece world.