Vegapunk

Doctor Vegapunk (Dr.ベガパンク, Dokutā Vegapanku) is the leading scientist in the employment of the Marines. His work includes discovering the secrets and uses of Seastone, the secrets of how Devil Fruit powers work, and various other scientific achievements. Vegapunk has a bodyguard called Sentoumaru.

Abilities and Powers
Vegapunk is a genius scientist whose scientific expertise is said to be so great that it would take other scientists 500 years to be as good as him.

Through his research he discovered ways of allowing Marine ships to pass through the Calm Belts by covering the bottom of the ships with Seastone. He also discovered exactly how Devil Fruit powers are transferred over to a user and was the discoverer of the method of adding such power to objects.

He is also the one who modified Bartholomew Kuma into a cyborg. He also produced many Pacifista replicas of Kuma, granting them the abilities of Kizaru's Devil Fruit in the process. These replicas bleed real blood, but lack Kuma's own Devil Fruit powers.

Trivia

 * In relation to a question asked by a fan about how come Luffy's Devil Fruit was already in the Devil Fruit encyclopedia when he ate it, Oda hinted that Vegapunk might know what Devil Fruits really are.