mirco demuro
Italian jockey based in Japan. He is infamous for his victory jumps and his love for nattou and other soy products, making him very memeable.
His brother, Cristian Demuro, is also a jockey who has also ridden in Japan.
If you see any of the below horses in their Umamusume form jumping like crazy or in midair, praising nattou and/or eating nattou, they likely are references to him.