In the comics, he actually sent Mera to charm Aquaman and then backstab him by killing him, although his plan is foiled when Mera actually falls for Arthur Curry.
Because Aquaman had already signed on two villains before adding Dolph Lundgren’s character, it’s probably better if Nereus isn’t a full-on villain.
If he’s definitely not going to be a villain in the movie, what does that make him?
Alright, so Dolph Lundgren is for sure joining Aquaman.