The Three Kings of West Blue (Also known as the Three Kings) are a group of three controlled by the World Government to guard three cubic relics that help pirates go to Frabara Island. The members of this group include Urako, Dinno, and Terro. Their names are based on the Spanish names for one, two, three, that being uno, dos, and tres.
Power & Devil Fruits
The Kings are very powerful, as seen when Terro defeated the Straw Hat Pirates. The other members are weaker than the Straw Hat Pirates, but they still gave them a run for their money. Their Devil Fruits include the Ningyo Ningyo no Mi (A Puppet Paramecia), the Heri Heri no Mi (A Helium Logia), and the Buru Buru no Mi, Model: Ox (A Ox Zoan). The Kings use their Devil Fruits wisely.
To see this, check out the members's pages.
Three Kings of West Blue vs Straw Hat Pirates: Loss