Black Manta was a regular man who designed a high-tech swim suit, and used it to battle Aquaman at different stages.
We haven’t seen much of Jason Momoa’s Aquaman, though he was featured prominently in the Justice League footage Zack Snyder brought to San Diego Comic-Con.
So far, in the DCEU, we have been exposed to a number of members of the developing Justice League.
In the New 52 universe, Black Manta has a long history with Aquaman and a team known as The Others, who were created from Atlantean relics.