Red Hare is a Rider-class Servant summoned by Ritsuka Fujimaru in Fate/Grand Order's Lostbelts.
Best known as the legendary steed of Lü Bu, Red Hare earned its fame through a Chinese saying: "Among men, Lü Bu; among horses, Red Hare"—essentially ranking them as the ultimate warrior and mount respectively. The horse was fiercely loyal, bonding with no one but Lü Bu himself. There's a famous story of Red Hare clearing a castle trench in a single jump, reportedly over 30 meters across.
Lü Bu himself was a legendary general whose deeds are immortalized in historical texts and novels like the Romance of the Three Kingdoms. Known as the Flying General, he was renowned for his fearless combat prowess and fought relentlessly throughout his life. He and Red Hare became inseparable on the battlefield, their partnership becoming the stuff of legend.
Content compiled by AnimeList.moe from publicly available sources.
