When the Frank Miller 300 comic book adaptation came out in 2007, no one really knew who director Zack Snyder or star Gerard Butler were. Jump to the present and those two are now both quite famous... and all the busier for it. Hence why they aren't reuniting for the prequel/spinoff project, 300: Battle of Artemisia.
Noam Murro is attached to helm Battle of Artemisia, which producers Mark Canton and Gianni Nunnari recently confirmed is indeed “a work in progress… as opposed to a year ago where it was just something we wanted to do.” Hence why the search is now on to secure a worthy leading man to play (essentially) the film's protagonist: the famed Greek general and archon, Themistocles.
Vulture is reporting that Joel Edgerton has begun talks with Warner Bros. officials to portray Themistocles in Battle of Artemisia - which, as it were, was actually scripted by Snyder and his 300 co-writer Kurt Johnstad, based on Miller's still-being-written comic book creation, Xerxes.
Edgerton, like Butler, is known for portraying (often bearded) gruff and physically-intimidating men onscreen. The former has also become a bigger name recently, thanks to strong performances in films like Animal Kingdom and Warrior - not to mention, his smaller (but still noteworthy) role in The Thing. On top of that, Edgerton is currently starring in Baz Luhrmann's The Great Gatsby adaptation and remains onboard to headline Kathryn Bigelow's untitled black ops thriller (previously known as Kill Bin Laden).
[UPDATE: Variety says that Edgerton has passed on Battle of Artemisia.]
While Xerxes (played by Rodrigo Santoro in 300) is the main character in Battle of Artemisia, he still remains somewhat of an antagonist - seeing how the film revolves around the Persian leader as he develops a god complex and wages war against Themistocles. Their conflict reaches a climax with the Battle of Artemisium, which occurs at the same time as the Battle of Thermopylae in 300.
Hence why there have been (unsubstantiated) rumors about Butler possibly making a brief appearance as King Leonidas in Battle of Artemisia - alongside Lena Headey, who would reprise her turn as Queen Gorgo from 300.
It is expected that Murro's Battle of Artemisia will retain the hyper-stylized aesthetic of the settings and combat sequences in Snyder's 300, if only to lend it similar commercial appeal (and, arguably, for continuity purposes). The former will also feature a more complex storyline and nuanced character portrayals, seeing how the film aims to show Xerxes in a more empathetic light than 300 did. So, it would make sense for the part of Themisticles to likewise require an actor who can infuse a badass character role with more depth - and Edgerton definitely fits the bill, in that regard.
That's all to say: if Edgerton does sign on, it'll be all the more reason to give this 300 flick a shot.
We will continue to keep you posted on the status of 300: Battle of Artemisia as the story develops.