Umamusume: Pretty Derby has turned out to be one of the most popular games in the world, partly due to being a gacha game and partly due to making pretty girls out of very real Japanese racehorses (which introduces a unique mourning when the real horse passes away and the anime girl lives on). A new kind of mourning faces the Umamusume fanbase now, as an upcoming stop on the game’s The Stage: World Tour at Los Angeles’ Peacock Theater…