As far as his future in the DC Extended Universe goes, there will surely be opportunities for him to return in specific Aquaman sequels, but it’s noteworthy that he’s been a part of some very important supervillain teams, including the Legion of Doom and the Injustice League (which is hinted at in the post-credits of Zack Snyder’s Justice League).
Real name David Hyde, Black Manta was created by Bob Haney and Nick Cardy and introduced in September 1967’s Aquaman #35.
He was initially portrayed as mysterious, powerful villain, notably outfitted with a large oval helmet with red glowing eyes, and it wasn’t until the early 1990s that his origin story was explained.