oju chosan (racehorse)
Retired Japanese race horse. He is the highest earning steeplechase race horse in the world, with an astounding 6 wins at the Nakayama Grand Jump, the last of them winning just 13 days after his 11th birthday.
While the horse, or steeplechase racing in general, has not made an appearance in Umamusume, fan artists tend to depict an OC-version of the horse hanging around with Gold Ship and other Stay Gold-related characters, as Oju is sired by Stay Gold (and shared temperment issues in real life).