One of the real-world racehorses that inspired a character in Umamusume: Pretty Derby has passed away, leaving behind a celebrated career as one of Japan’s most respected champions. The horse-racing simulation, known for its anthropomorphized depictions of famous racehorses, has been a global hit since its worldwide release in late June. Its Steam launch quickly attracted tens of thousands of players, even surpassing notable titles like Persona 5: The Phantom X during its debut week. Now, the community is mourning the loss of one of the game’s most beloved inspirations.
Umamusume: Pretty Derby features a wide roster of characters, each based on real-world racehorses. Popular names like Special Week, Tokai Teio, and Oguri Cap have become central figures in both the game and the anime adaptations. Players can also challenge famous races, including the Japanese Triple Crown and Triple Tiara. Grass Wonder, one of the most prominent horses in Japan’s racing history, was among the standout inspirations in the franchise.
Cygames officially shared the news on August 9 via its English X account, confirming that Grass Wonder passed away on Friday, August 8, 2025. The announcement included condolences for the many staff members who had cared for him throughout his life. Grass Wonder last raced professionally in 2000 and was part of Japanese horse racing’s “Golden Generation,” alongside Special Week, Seiun Sky, and El Condor Pasa.
During his illustrious career, Grass Wonder claimed four Grade 1 victories, including consecutive Arima Kinen wins in 1998 and 1999, as well as the 1999 Takarazuka Kinen. These races also saw him compete against Special Week, cementing their rivalry in horse-racing history. Grass Wonder had celebrated his 30th birthday earlier this year in February, a milestone rarely reached by thoroughbreds.
Within Umamusume: Pretty Derby, Grass Wonder is a two-star Trainee and played a significant role in the first season of the anime. The character has also received alternate versions in the Japanese client, such as “Fantasy” and “New Year’s” outfits, with more variations expected in future updates. Fans will have many opportunities to honor Grass Wonder’s legacy in-game, keeping his memory alive for years to come.
Grass Wonder’s passing marks the end of an era for both Japanese horse racing and the Umamusume community. His remarkable career and the joy he brought to fans—both on the track and in the digital world—ensure that his legacy will not be forgotten.