‘Game of Thrones’ Aegon’s Conquest Spinoff in the Works From ‘The Batman Part II’ Writer (Exclusive)

HBO is developing another Game of Thrones spinoff series.

The company is actively heating up its long-in-discussion Aegon’s Conquest idea.

HBO is partnering with Mattson Tomlin, an in-demand scribe who did uncredited work on Matt Reeve’s The Batman and is co-writing its upcoming sequel, The Batman Part II. He also wrote the Keanu Reeves action comic adaptation BRZRKR and an animated Terminator series which he is also showrunning for Netflix.

Aegon’s Conquest is basically a direct prequel to the hit House of the Dragon, telling the story of the Targaryen’s bloody and brutal conquest of Westeros. The story follows the invader Aegon Targaryen, who conquered the continent of Westeros with his sister wives, Rhaenys and Visenya, and their dragons. Aegon successfully unified six of the Seven Kingdoms in just two years, with only Dorne able to successfully resist.

One source described the project as taking a “back to basics” approach to George R.R. Martin’s epic fantasy universe (though considering the first series was sprawling and complex, it’s unclear what “back to basics” means, exactly, in the Thrones context). Variety previously reported Aegon’s Conquest as an idea in discussion early last year.

Since Thrones concluded in 2019, there have been many prequels (and one sequel idea) put into development and some are considered no longer active — though HBO prefers not to say any option is completely off the table as there’s always the chance a once-promising idea could be redeveloped under a different writer.

The efforts have spawned two greenlit shows: House of the Dragon, which launches its second season this summer; and A Knight of the Seven Kingdoms: The Hedge Knight, which starts production this year and is based on Martin’s Dunk and Egg novellas.

HBO had no comment.

Tomlin — repped by CAA, Brillstein Entertainment Partners and Goodman Genow — has shown he can flex in various genres, wrote the Jamie Foxx Netflix superpower crime thriller Project Power and worked as a consultant on the Oscar-nominated animated movie The Sea Beast.