Trebol

Trébol is a member of the Donquixote Pirates.

Appearance
Trébol is a very bedraggled individual. He has dark hair that is worn as a bowlcut. He wears a small pair of sunglasses and has a broad flat nose, which is commonly seen with some snot hanging out. He has a long, thick beard and some stubby hair on his upper lips.

His lips are a bit thicker than normal and his teeth are round and have some space between them. He has a prominent hunch and appears to be considerably taller than normal people, although the hunch takes some height away. His attire consists of a long coat with a ring-pattern on it, which resembles that of the Smiles.

Personality
Trébol seems to have problem with how close he gets to someone with whom he is talking, making people comment that he is too close.

He is also somewhat bold and insensitive, as he casually asked Baby 5 if Doflamingo killed another of her fiancés, as well as asking Baby 5 to marry him as a joke, knowing that it would make Baby 5 feel compelled to help him out.

Doflamingo
Trébol is very casual around Doflamingo and doesn't seem to be scared of him, as he get awkwardly close to him, much to his annoyance. Trébol often refers to him by his nickname "Dofy".

Baby 5
Trébol is somewhat rude towards Baby 5, as he casually asked her if Doflamingo killed another of her boyfriends, as well as making fun of her inability to say no to people.

Unknown ability
Trevor was seen to have the ability to transform into a sticky liquid of some sort, which allows him to stick to walls.

Dressrosa Arc
Trébol is first seen when Baby 5 is looking for him, sticking onto the wall of a house, remarking that the country is in chaos and suggesting that the rest of the world is in chaos too. He then rushes up to Baby 5, getting way too close to her, and asks her if it's true that Doflamingo killed another of her boyfriends, only to be told to back off. Trébol starts flirting with Baby 5 for a bit, to which Baby 5 tells him that he's gross and that Doflamingo wants to see him and that Trébol brings it with him. He then suggests that Baby 5 should marry him instead of some random man who'll only get killed by Doflamingo but quickly laughs it off, as a joke.

Later, in Doflamingo's meeting room, Trébol drops himself off the ceiling and hands Doflamingo the object he desired, getting too close to him again. The object is then revealed to be the Mera Mera no Mi.

Trivia

 * "Trébol" is the Spanish word for clover. This matches the card suit motif of Doflamingo's subordinates, as the clubs suit is called "tréboles" (clovers) in Spanish.
 * Like most One Piece characters, Trébol has a distinct laugh: "Behehehehe".