Diamante wears a light colored hat with brown locks of hair coming down from it. He has striped, orange and red rectangular streaks that run down from his forehead, through his eyes, straight to his chin. According to anime, his eyes are blue. He wears a pink shirt with purple pants and a crimson cape made of steel. He is an extremely tall and thin man, at least a foot taller than Doflamingo who is 10 feet tall himself, and possesses a muscular upper body. His legs are especially long, protruding out right next to his face when he sits down. Of the top three executives of the crew, he is the lankiest and thinnest.
Ten years ago during the takeover of Dressrosa, the streaks on his face were not present.
Every time someone says something flattering or good about Diamante, he denies it until the person flattering him stops. That is when he accepts the compliment, and believes that the person praising him had offered his or her unbiased opinion about his talents. 
He is also seemingly cruel, as he spoke to Bellamy extremely harshly after he was beaten in the Colosseum. During the usurpation of the Riku Family, he was seen smiling during the burning down of the castle, indicating his joy during the event. Diamante also is rather insensitive and he was beginning to willingly tell Rebecca about her mother's death on top of mocking her father for his sorrow over her loss.
Diamante does not seem to give in to popular opinion as he remained steadfast in declaring Rebecca the winner of block D when some other gladiators tried to attack her, showing at least fair sportsmanship.
He also considers his crew as his family, being visibly mad and stunned when a Donquixote soldier laughed at Pica's high pitch voice.
Abilities and Powers
As the director of the Corrida Colosseum, he is in charge of all the goings on in the building. He is also known as the "Hero of the Colosseum" on Dressrosa, for which Doflamingo holds him in high regard. In addition, he sits in Doflamingo's diamond chair, one of the four Top Executives of the crew.
Doflamingo trusts Diamante enough to fight all of the block winners in the tournament alone, as the Battle Brigade that he commands has been sent away to complete various tasks. This implies that Doflamingo has enough confidence in Diamante's strength and abilities to at least compete against, if not defeat, Jesus Burgess, Bartolomeo, Rebecca, and Lucy by himself. He is also immensely durable and strong, as he was not bothered by Rebecca striking him in the leg with her blunt sword.
Diamante ate the Hira Hira no Mi, a Paramecia-class Devil Fruit that allows him to flatten anything he touches like a flag and reform and fold it while still retaining its original characteristics.
Diamante wears a steel block for a cape, which he uses in tandem with his Devil Fruit powers to make it flutter, while maintaining its steel quality for defense, capable of snapping cutlasses and injuring enemies rushing into it. For offense, he wields a flintlock handgun, to kill Rebecca's mother Scarlett, a rapier, which he can also use his fruit's powers to make it flutter, reshaping it into other shapes for attack, and a club he keeps folded using his fruit's powers, and can then unfold and make it regain its shape to attack.
He participated in Doflamingo's takeover of Dressrosa. After Doflamingo successfully made Riku Dold III a villain in the citizens' eyes, Diamante, Trébol, and Pica stepped in and subdued the Dressrosa army, passing themselves off as heroes. Diamante also pursued Scarlett and Rebecca until Thunder Soldier intervened. While Scarlett was getting food for her daughter, Diamante shot her.
As time went on, Diamante had become loved by the people in the Corrida Colosseum, becoming its properitor known as the "Hero of the Colosseum" and earned a high rank in Doflamingo's army sitting in the Diamond chair.
Later he was seen in the Corrida Colosseum, where he was announced after the four other Donquixote Family members as part of the tournament to win the Mera Mera no Mi.
During the tournament, he was watching the battle royale from the staff room above the stands. He was talking with Bellamy about the latter's assassination assignment, saying that Doflamingo was too soft to give him another chance. He told Bellamy that if he got rid of Luffy before the end of the tournament, he would become an officer within the organization.
While Law and Doflamingo were fighting on the iron bridge, Diamante contacted Doflamingo via Den Den Mushi and informed him about Violet's betrayal. Doflamingo then ordered Diamante to send Lao G and others to guard the underground factory.
When Franky attempted to breach the Toy House, Diamante heard the commotion through Den Den Mushi.
He entered the arena along with "Lucy", Burgess, Bartolomeo, and Rebecca. They were suddenly interrupted when some of the disqualified participants from Block D charged in, refusing to accept that Rebecca was the winner. Diamante repelled them with the power of his Hira Hira no Mi, telling them to accept their losses. Diamante then introduced a new type of Fighting Fish that can reach contestants in the ring and explained that the Mera Mera no Mi is in a chest on the back of one of those fishes. After Diamante declared that whoever can steal the chest and be the last person standing in this round's battle royale will be declared the winner, the match began.
When Lucy jumped on the fighting fish holding the Mera Mera no Mi, Diamante attempted to attack him in order to prevent him from acquiring the Devil Fruit. Much to his surprise, Lucy was able to block his attack and shatter his weapon. After Lucy shattered Burgess's armor, Diamante noted that Lucy's fighting style was different, due to the fact that this was not Luffy.
Later, Rebecca attacked Diamante, but her strike was ineffective because she was using a dull blade. Diamante retaliated by striking her with a club while saying that she will die if she is not willing to kill. He then mocked her about her mother's death.
He proudly revealed that he was the one who killed her mother and smiled as Rebecca broke down in tears.
As the toys in the audience transform back into their original forms after Sugar's curse broke, Diamante was deeply displeased with Trébol's failure. He was then surprised when Lucy demolished the entire arena with his bare hands.
As the arena collapsed, Diamante was submerged and unable to stop Lucy from acquiring the Mera Mera no Mi. When Lucy's helmet and fake beard fell off, Diamante noticed that he was from the Revolutionary Army. After Lucy destroyed the arena, Diamante fell into the underground trade port. While wondering what to say to Doflamingo, he saw the slaves freed from Sugar's curse charging at him.
He was later seen with Trébol guarding the SMILE factory, having defeated many attackers.
Diamante and Trébol later gathered at the royal palace, which has been relocated to the top of the Flower Hill by Pica. Diamante tried to make an excuse for losing the Mera Mera no Mi, but Doflamingo pardoned him for his failure. After Diamante asked Doflamingo about what they should do about Issho, Doflamingo assured him that the admiral would not be a problem. When one grunt laughed at Pica's high voice, Diamante, along with the other Executive Officers and Doflamingo, glared at the man angrily.
Later, as Luffy and his allies fought their way to the palace, Diamante stood next to Doflamingo and talked about the time they first met Law. Diamante then waited at the Flower Field and confronted Rebecca once she arrived.
- Diamante, Trébol, and Pica vs. the Dressrosa army
- Diamante vs. Thunder Soldier
- Diamante vs. fighters from block D
- Corrida Colosseum Finale
- Diamante and Trébol vs. former toys
- Diamante is the Italian, Spanish, and Portuguese word for "Diamond". This matches the card suit motif of Doflamingo's top executive officers, as the diamond suit is called "diamante" in Spanish.
- The manner in which he utilizes his cape and rapier is reminiscent of a Spanish bullfighter, using their cape to distract the bull before striking it with a rapier.