Ucy is a fighting bull (闘牛 Tōgyū?) who is well-known as the Brutal Bull. He competed as a gladiator in the Corrida Colosseum, where he befriended and was given his name by Monkey D. Luffy. He would serve as an ally of Luffy during the Dressrosa Arc.
Ucy is a large bull with dark fur, long horns (the left of which was later broken due to Hajrudin) and a bulky body. He also has small eyes, both with three eyelashes on each.
He is described by Gatz as the "Colosseum's Grim Reaper", and his fighting style has led him to become known as the "Brutal Bull". Despite this, Luffy was still able to tame and befriend him using his Haoshoku Haki.
Abilities and Powers
He is powerful enough to eliminate many competitors of Block C. He is also said to have eliminated many death row prisoners in the past, a further testament to his fighting prowess. However, he was no match for Hajrudin, as he was defeated in one blow by the giant. In spite of the injury he received during the tournament, he was able to recover later to help Luffy reach Doflamingo.
During the battle royale, he was tamed and ridden by Lucy, and was dubbed Ucy by the disguised Straw Hat captain. Charging into the midst of a large number of combatants, he swiftly eliminated them, only to accidentally run into Hajrudin's leg. Taking this as a challenge, the giant attacked the two friends, smashing them both into the ground, which rendered Ucy unconscious and broke its left horn. Angered by the giant's attack on his newfound friend, Lucy avenged Ucy by knocking Hajrudin out with one blow. He then carried Ucy away to a safer part of the ring. 
He later went to the underground medical treatment facility to receive treatment for his injuries.
After Doflamingo trapped Dressrosa in his "birdcage", he went to the surface. After finding and recognizing Luffy, he joined forces with him alongside the Chinjao Family, Hajrudin, Cavendish, Ideo, Elizabello II, Dagama, Blue Gilly, Abdullah, Jeet, Orlumbus, and Suleiman. They later marched towards the palace and began to battle against Pica.
When Pica attempted to strike, Chinjao and Elizabello II shattered Pica's stone hand, enabling the group to move forward. Pica then attacked with his other arm, causing Luffy's allies to fall back. However, Ucy, with Luffy, Zoro, Law, Abdullah, and Jeet on its back, jumped on and ran on Pica's arm. After Luffy shattered Pica's stone head with Grizzly Magnum, Pica's true body appeared before the bull. Pica took out his sword and tried to attack the bull and the group riding on it, but Luffy carried the bull and evaded the sword strike. Zoro intercepted Pica when he attempted to strike again. With Pica held back, Ucy ran on the stone giant's back, carrying Luffy, Law, Abdullah, and Jeet closer to the palace.
They eventually reached the first level of the new King's Plateau. While they charged through Doflamingo's troops, Kelly Funk (while fused to Bobby Funk) appeared seemingly to aid them and showed them a tunnel that is supposed to go directly to the fourth level. While entering the tunnel, Abdullah and Jeet fell off Ucy so he, Luffy, and Law went ahead without them. Instead of reaching the fourth level, they reached a dead end where they found themselves above a pool of water. They were then ambushed by Doflamingo.
Doflamingo attacked Ucy with a bullet thread, knocking him unconscious. Ucy, Luffy, and Law were saved from death by the timely arrival of Abdullah and Jeet, who both struck Doflamingo (who was only a string clone) in the back. After Luffy punched a hole to the second level, he left Ucy with Abdullah and Jeet.
- Brutal Bull vs. death row prisoners
- Ucy vs. Corrida Colosseum Group C Gladiators
- Ucy vs. Donquixote Pirates' troops
- Ucy vs. Luffy
Manga and Anime Differences
- In the anime, "Brutal Bull" has been used as the character's name, rather than as an epithet. "Fighting bull" has only been used to describe him, just as "fighting lion" describes Agyo.
- The name was mistakenly romanized as "Brutal Bule" when the gladiators were introduced at the beginning of Block C.
Fighting Bull appears in the first part of the Heroes: One Piece Dressrosa Arc figure set.
- Luffy's nickname for the Fighting Bull, Ucy, is a pun based on his own gladiator name Lucy (ルーシー Rūshī?), and the Japanese word for Bull (牛 Ushi?). The syllables "U" and "shi" are stretched out to match the pronunciation of Lucy ("si" and "shi" are written and pronounced the same in Japanese). The VIZ Media translation compensates for this by using the name "Moocy" instead.
- In an SBS, Oda stated which animals best represent each member of the Worst Generation. He stated that Eustass Kid was best represented by a "Fighting Bull".
- FUNimation replaced Ucy's English voice actor after Chris Thurman admitted to sending explicit photos to a minor.