The beginning of the movie sets up Kane’s motivations against Aquaman, since he leaves him helpless to watch his father die following their pirating of a submarine.
In between King Orm’s plot to rid the world of land people, Yahya Abdul-Mateen’s character of David Kane/Black Manta shined with his own origin story.
Kane then teams up with Orm, recieving Atlantean technology that allows him to build the iconic Black Manta suit and come up against Arthur on land.