Jailer Beasts

The Jailer Beasts number five and rank as the most feared monsters within Impel Down, serving directly under the demon guard Sadi. Each takes the form of a colossal two-legged animal, typically clad in pants but no shirt, sporting runny noses and, for most, deceptively adorable eyes that mask their brutal reputations. The original four are Minotaurus the cow, Minorhinoceros the overall-wearing rhinoceros, Minokoala the koala, and Minozebra the zebra, with Minochihuahua the chihuahua joining their ranks later.

Behind their comical looks, all five are merciless brutes who torment the prison's inmates, making them the most terrifying presence in Impel Down apart from Magellan. Their strength stems from being awakened Zoan Devil Fruit users, which leaves them extraordinarily tough and quick to mend from injury. That awakening came at a steep cost, however, since it went wrong and let the animal instincts overrun their human minds, reducing them to simple beasts. They remain obedient enough to follow the human guards' orders and visibly fear Sadi's temper. Even so, they sit below Magellan, Hannyabal, and Sadi in the prison's hierarchy, and powerful fighters can bring them down.

Minotaurus wields a giant mace and combines fearsome speed with raw power. Minorhinoceros, bashful by nature, swings two spiked maces, while the shy Minozebra uses a long-shafted mace and once hurled prisoners into the Pond of Blood. Minokoala fights with spiked knuckles, and the later addition Minochihuahua carries a rope, its full abilities still a mystery. During the Impel Down breakout, the beasts repeatedly tried to halt Luffy and his allies but were beaten back by the combined might of Luffy, Jinbe, and Crocodile, who were the first to recognize that the guards were Devil Fruit users at all.