Sibling rivalry is as much a thing in comic books as it can be in real life. In fact, it’s a recurring theme in many Aquaman comics, particularly when dealing with a certain villain...

While Aquaman has experienced his ups and downs—both in terms of popularity and respect amongst others in the DC Universe—one thing that has remained pretty consistent is his relatively small (but solid) rogues gallery. The problem is that outside of Aquaman’s devoted fanbase, most people aren’t all that familiar with it. They might know Black Manta. He’s probably the most popular and well-known Aquaman villain.

But they may not know Ocean Master.

That’s likely to change soon. As anyone who has looked into the upcoming Aquaman movie, or seen the recently released trailer, can tell you, Ocean Master is the movie’s core villain. So, who is he?

Like many characters, Ocean Master has gone through his fair share of revisions in the years since he was first introduced to us. Regardless of the character tweaks and retellings, he has managed to stay relevant in both Aquaman’s world and the DC Universe as a whole.

Ocean Master made his comic book debut in 1966’s AQUAMAN #29. Unlike a lot of villains at the time, Ocean Master’s initial clash with Aquaman wasn’t a head-on physical encounter. Sensing the world’s navies on his heels, Ocean Master sends a ransom video of sorts proclaiming that there will be a series of strikes made against various nations around the world unless said navies cease hunting him. To flex his scientific and weaponry muscle, and to show he’s serious, he maroons a huge ship atop an iceberg in the ocean.

Aquaman and Aqualad soon discover that Ocean Master’s ultimate plan involves a whale (it’s always a whale) that’s fitted with a device designed to set off a chain of disasters as the whale follows its ocean-wide migration path. Ultimately, Aquaman and Aqualad save the whale and foil Ocean Master’s plans…but not before Ocean Master can escape.

The twist of the story comes when Aquaman reveals that Ocean Master is actually his half-brother. Arthur explains that his father remarried after his first wife died. Soon after, they had a son, whom they named Orm. Since Aquaman’s mom was Atlantean, he inherited her underwater abilities—abilities the fully human Orm lacked. This always enraged the younger brother, as he felt inferior to Arthur, who was older, bigger, stronger and had superpowers to boot.

This anger consumed Orm and ultimately put him on the path of crime. Orm eventually received a head injury that resulted in him forgetting who he and Aquaman were. Despite the injury, however, Orm stayed on his bad path before disappearing and then reappearing years later as a high-tech criminal pirate.

Over the years, Ocean Master remained a thorn in the side of Aquaman—increasing his evil intentions to major crimes like holding the world at ransom through high-scale attacks in the form of large “natural” disasters.

In the early 1990’s, writer Peter David took over the new Aquaman monthly title and with it, revamped the origin story of both Aquaman and Ocean Master. In this version, the two remained half-brothers, but instead of sharing the same human father (with differing mothers), David made them the sons of Atlan the Wizard—an ancient Atlantean magician. Orm’s mother was an Inupiat woman. The two would be destined to be enemies the rest of their lives.

A few years later, Orm would gain immense power after obtaining a magical trident from Nero. This would propel him into the realm of mystical powers and help him eventually conquer the Dreaming City (an Atlantean nation) and soon be able to alter time in order to switch places with Aquaman.

Fast forward a couple of decades to 2011, and writer Geoff Johns reboots Aquaman from the ground up as part of what's referred to as "The New 52." Arthur and Orm remained linked as half-brothers, but Orm is full-Atlantean and was made the King of Atlantis through a number of suspect events. He was eventually deposed after waging war on the surface world, after which Arthur became king (in a popular Johns storyline that seems to have influenced the upcoming film).

Ocean Master has displayed a knack for high-tech gadgets and weaponry, which he supplements through the use of magic and mystical abilities. Being amphibious, he can breathe underwater and swim at great speeds. His signature helmet and trident are part of his iconic look, but are also functional weapons—particularly the trident, which allows him to control large amounts of water and fire energy blasts. Don’t sleep on that sleek stingray chest emblem, either—it’s one of the coolest.

Never one to shy away from collaborative efforts, Ocean Master has occasionally partnered with other villains over the years, including Black Manta and groups like the Injustice League and the Secret Society of Super-Villains.

So, if you find yourself out to sea…or in the movie theater this December for Aquaman (more likely), you’ll now have some background on Ocean Master. Just don't mention his half-brother!

Aquaman, directed by James Wan and starring Jason Momoa, splashes into theaters on December 21, 2018.