Stansen is a giant from Elbaph, who is a shipwright. After being imprisoned in the Auction House, he was freed alongside other slaves by Silvers Rayleigh during the Straw Hat Pirates’ assault on the business.

Afterwards, Stansen became a member and the shipwright of the New Giant Warrior Pirates, and the crew became S-Class soldiers within the mercenary group Buggy’s Delivery. Upon his captain Hajrudin pledging his loyalty to Monkey D. Luffy, the crew left the organization.

He is a major ally of the Straw Hat Pirates during the Elbaph Arc.

(Source: One Piece Wiki)