Arthur Curry is a fictional male in the Justice League series. The character was portrayed on screen by Jason Mamoa. His allegiance / loyalty is to The Justice League. Contains Spoilers if you not seen the film.
In the films, Arthur Curry is introduced briefly in Batman Vs. Superman where we see a shot of Aquaman underwater. Aquaman didn't have a role to play in the previous film. On screen, his first appearance is in Justice League where the group of superheroes attempt to stop Steppenwolf, an alien from another world. Arthur Curry is the reluctant member of the group who needs to be convince to join.
Bruce Wayne has managed to track Arthur Curry to an Icelandic village where the legend has it a man comes bearing fish from the sea when all other food sources are scarce. Arthur Curry declines Bruce's request for help, instead Arthur just goes back into the water and swims away. When Steppenwolf steals the Mother Box, Aquaman joins the fight.
In the comics, Aquaman is a blonde man who can control water and talk to fish allegedly. His main weapon is a trident or five pronged fork as we see in the first outing of him in the movie. In the film, Arthur Curry is played by Jason Mamoa, a dark haired man with a little bit of blonde at the ends of his hair as a nod towards the blonde in the original comic series. Aquaman is heavily tattooed which is presumed another change from comic, not having read it myself tho.
The comic has him king of Atlantis, the city that sunk below the waves and wasn't seen again. Its not apparent as to his title in the film but its presumed not to be king. In the comics, his love interest is Mera. There is a brief view of Mera but she doesn't play too much of a part in Justice League. Mera and Aquaman are not an item in this film. To see more of Aquawoman, you will need to wait until the following year when Aquaman hits the cinemas. The main anagonist of Aquaman is Black Manta.
Copyright: DC Comics