"Ocean Master" is a title, somewhat akin to "emperor", granted to whoever can obtain support from at least four of the kingdoms of Atlantis. Other than his own kingdom, Orm manipulates Nereus of Xebel by staging a false flag attack with a human submarine, kills the Fisherman King and coerces his heir, Fisherman Princess into cooperating. He dons the suit into battle and defeats the Brine King, proclaiming himself "Ocean Master".
The suit is highly durable. Its helmet withstood repeated strikes from a massive propeller with no sign of damage. The face area also changes to reflect Orm's expressions.