Aquaman: 22 Easter Eggs & References Explained
18. Arthur "Kills" Black Manta's Father
The first time we see adult Arthur in the movie, he's attempting to prevent a nuclear sub from being hijacked by David Hyde aka Black Manta (Yahya Abdul-Mateen II), his father Jesse (Michael Beach) and their gang of armed pirates.
The ensuing fight results in Jesse being mortally wounded by Arthur and, following Arthur's departure, left to drown in the waterlogged sub.
In order to ensure his son's safety and spare himself a prolonged death, Jesse commits suicide by detonating a grenade, though considering how easily Arthur could've saved him, this forms Black Manta's revenge arc for the rest of the movie.
This is fairly in line with Aquaman and Black Manta's adversarial relationship from The New 52 comics, which isn't terribly surprising considering that Geoff Johns worked on both those comics and co-wrote this movie.
In The New 52, Arthur somewhat inadvertently caused the death of Black Manta's dad, also on a boat no less.
This follows last year's Wonder Woman movie also being comprehensively influenced by The New 52 iteration of the character, which given its general success among fans makes a lot of sense.