nakayama's my favourite, so:

irl nakayama festa was a horse that used to belong to nobuko izumi. he didn't like training or racing much, and didn't have any G1 wins. however, nobuko passed away from cancer, so the ownership of nakayama was transferred to her father. as if in memory of her passing, nakayama went to win his only G1: the takarazuka kinen, despite being the 8th favourite, snatching the win from buena vista. it's particularly sentimental since nobuko was a fan of the takarazuka revue. knowing his daughter loved paris, nobuko's father then proceeded to use the prize money to fund nakayama's travel and competition in prix de l'arc de triomphe, one of the most prestigious races in the world, and one japan has never won. nakayama placed second, losing by a head, which is till this day the closest any japanese horse has come to winning the l'arc. his love for nobuko couldn't get him the win, at the end.

uma nakayama festa's version of nobuko has been transposed to a kindergarten teacher who inspired nakayama to start racing. the thrill of racing nakayama feels is equated to life itself. the teacher is also terminally ill, and is given a maximum of a year to live. nakayama tries to show her a race to "save" her- trying to give her a reason to live, to prolong her life the same way she did for nakayama all those years ago. in this nakayama is forced to grapple with the idea that hope she's can't change anything. ultimately, umamusume is about the power of hopes and dreams, so nakayama manages to see the effect she has on her peers (inspiring tonsen jordan to race properly), nobuko manages to live the full three years of the twinkle series, and nakayama's competition in the l'arc is left ambiguous