The book is written as an in-universe artifact from the perspective of Arthur Curry as a teenager. His entry on Xebel notes that it is ruled by King Nereus, played by Dolph Lundgren.
"Vulko says the king has a family," the entry reads. "Apparently he has a daughter my age named Mera. Kinda sorta jealous that she's down there and I'm up here."
"Down there" and "up here" presumably refers to the surface, Atlantis, and Xebel's relative locations to each other. It seems young Arthur had an interest in Mera even before meeting here, likely coming from what seems like a lonely childhood for the Atlantean prince.
The entry also includes a photo of a Xebellian polearm. Take a look below.
In previous statements, Lundgren seemed pretty pleased with his royal role in Aquaman.
"It is good to be king. Basically, I try to keep the peace down there along with Amber Heard, who plays my daughter," said Lundgren. "She's trying to convince me to join the right side. Then you have Nicole Kidman as Aquaman's mother [Queen Atlanna]. We're trying to avoid war between the surface dwells and the people of Atlantis."
King Nereus' queen is also Aquaman's mother, born to her and a lighthouse keeper named Thomas Curry. Atlanna's royal responsibilities forced her to return to her underwater home, leaving her son behind with his father. You can read her letter to Arthur here.
Aquaman's royal lineage makes him a threat to his half-brother, Atlanna's other son and current ruler of Atlantis Orm, aka the Ocean Master, played by Patrick Wilson.
"He's kind of an eco-warrior," Wilson has said of the character, who wants to unite the seven tribes of Atlantis to wage war against the surface-dwellers. "He's got a very clear gripe with the surface world, which has been polluting his oceans for centuries. And that's something for me — I'm sure for you too — that's very easy to understand. If somebody was just constantly polluting our air and ruining how we lived …"
Are you excited about Aquaman? Let us know in the comments!
Aquaman opens in theaters on December 21st.
Other upcoming DC Extended Universe movies include Wonder Woman 1984 on November 1, 2019, Shazam on April 5, 2019, Birds of Prey on February 7, 2020, Cyborg in 2020, and Green Lantern Corps in 2020.