Wynn Trevor

Wynn Trevor is a marine and the brother of Wynn Erin. He lived in his brothers shadow for years, being ignored by his father as he wanted to focus on his brother more. When his brother defected though, Trevor became the focus of his father's affections and harsh training. Trevor was worked for most of his life, trained personally by his father until he became a captain, where he then worked himself up to the rank of commodore. Trevor ate the Kagi Kagi no Mi slightly after his brother left, becoming a key human. Using this power he became quite the force to be reckoned with in Paradise.

Devil Fruit
The Kagi Kagi no Mi is a powerful that gives Trevor the ability to create, manipulate, and use keys for various purposes. One of the strengths of this fruit is that it gives Trevor the ability to generate large amounts of keys of all shapes and sizes, as well as control them. Trevor can create multiple small keys and cause them to swarm opponents. He can also design the keys with sharp features allowing them to possibly create minor cuts or wounds when the keys hit people. This devil fruit has a much greater power however. Trevor can generate special keys that can unlock or lock any lock. This is extremely helpful in espionage or simply treasure hunting. Trevor is also capable of generating keys that can unlock or lock other things such as potential, memories, or bodily functions such as sight or movement.

This fruit does not really suffer from any specific weaknesses besides the standard devil fruit ones. However if Trevor unlocks someone's potential, including his own, it will cause that person great strain if they cannot quite handle it.

Busoshoku Haki
Trevor is quite skilled in the use of Bososhuko Haki. With this power he is able to create an invisible armor around himself. This armor can defend against seriously powerful attacks, though with enough force or a more powerful haki user it can be broken. Wynn can also extend his haki to his weapons. This invisible armor gives him the ability to hit users of logia and some paramecia fruits. He can use this to hit their actual body, negating one of the huge advantages of a logia.
 * Busoshoku: Koka: Trevor is capable of using this technique to enhance his haki. With it he can harden various parts of his body, giving them a black coloring and severely increasing his strength and durability on those parts of him. He usually uses this on his keys to make them extremely durable.

Trivia

 * His last name comes from Emanuel Wynn, the first pirate to fly a jolly roger.