2220 BCE - 26-year-old Teth-Adam earns the role of Shazam's champion, becoming Mighty Adam.
2140 BCE - 106-year-old Teth-Adam loses everything when Khandaq is overthrown by Ahk-ton for Vandal Savage. He kills Ahk-ton & becomes the new ruler of Khandaq, ruling with an iron fist to protect his people.
2137 BCE - 109-year-old Teth-Adam loses the favor of Shazam because of his methods and becomes Black Adam. His power is stripped from him, killing him. His people entomb him with honors.
52 years ago - Theo Adam is born, reincarnated from Teth-Adam.
34 years ago - 18-year-old Theo begins studying archeology.
30 years ago - 22-year-old Theo fakes his credentials & starts working digs in Egypt.
26 years ago - 26-year-old Theo begins robbing tombs.
21 years ago - 31-year-old Theo is almost caught. He goes legitimate & becomes a guide.
11 years ago - 41-year-old Theo meets the Batsons. They find a tomb that draws him, he kills them to steal the amulet worn by Teth-Adam.
6 years ago - 46-year-old Theo's past life memories are awakened when Captain Marvel becomes the new champion of Shazam. He returns as Black Adam, battling Marvel.
3 years ago - 49-year-old Black Adam rediscovers his purpose. He abandons his Theo Adam identity & retakes the throne of Khandaq, bringing Northwind into his court.
2 years ago - 50-year-old Black Adam is given Adrianna Tomaz as a gift. He kills he captors and takes her into his palace. She impresses him with her fearlessness & inspires him to focus on the well-being of his people, sharing his power with her so she becomes Isis. They are soon married making her the Queen of Khandaq.
Black Adam is a character that's experienced massive growth and expansion over his history. He was created by Otto Binder, the man responsible for the massive success of the Captain Marvel franchise over in Fawcett Comics before they were sued out of existance by DC for mimicing Superman (which might have been a valid claim, but only inasmuch as EVERY superhero, in one way or another, is mimicing Superman.) Binder's contribution to the Captain Marvel lore is the 'Marvel Family', a ever-growing collection of characters that all shared his powers and costume. This would obviously influence DC in the years to come as the tentpole characters would gradually be surrounded by various suporting casts of similar sidekicks, but one of the most lasting elements of Binder's 'Marvel Family' was an actual evil counterpart to his hero. Not just a Lex Luthor to his Superman or a Joker to his Batman, but a mirror version of Captain Marvel with all the same powers.
We've seen this since then, obviously. Marvel does it quite a bit, creating a direct evil counterpart to it's heroes whether it's Sabertooth for Wolverine or Venom for Spider-man, But it's pretty safe to say that Binder was the first, and to do it with a character as powerful as Captain Marvel was a pretty bold move. These characters weren't meant to have limitations, they were child's power fantasies of the highest order. The implications of turning lose an evil version of such a character probably never occurred to old Otto, who likely never meant to have his creations interact with a more adult storyscape.
None of the Fawcett characters had regular roles in the DC Universe proper for a very long time, even after their corner of the Multiverse was folded into the singular post-crisis timeline, and likely for good reason. What do you even do with a villian this powerful? It was the continuity doctors of the modern JSA book; James Robinson & Geoff Johns, that came up with a modern interpetation lush with storytelling possibility. The relationship between the modern-day graverobber and murderer Theo Adam and the ancient Teth-Adam led to a fascinating dicotemy between his role as a villian and his desire to retain the brutal heroism of his past. By incorperating his ancient kingdom of Khandaq and making him the unquestioned ruler of the modern kingdom makes him DC's answer to Doctor Doom, to Black Panther... and all in a character so powerful that you could convincingly tell a story of him fighting ALL the superheroes on the planet. (which DC actually did, although we're not actually including the story of World War III).
The inclusion of his relationship with Adrianna Tomaz, and using it as a way to bring in the classic live-action character Isis into continuity was brilliant both because of the character it brought us, but also because it brings further depth to an already fascinating icon of DC's continuity.