Ocean Master’s appearances outside of the comics include the Justice League animated series, Young Justice and Justice League: Throne of Atlantis.
Introduced in 1966’s Aquaman #29, Orm shares the same mother as Aquaman.
As of the New 52, Orm is a full Atlantean, so while Arthur Curry grew up on the surface with his human father, Orm spent his formative years in Atlantis.
This resulted in Orm growing extremely jealous of his brother, and as Ocean Master, he’s used his abilities and special trident to challenge Aquaman repeatedly, all because he believes he knows what’s best for Atlantis.