While we knew that the upcoming show — which received a 10-episode order in June — would center around the game's most recognizable character, this is the first indication that production is actively underway, as the network is also looking for actors to portray Master Chief's fellow space marines.
As THR is right to point out, the casting of Master Chief will be interesting to see as the character's face is never shown in the games, nor is his voice heard very often. One of the most decorated soldiers in this futuristic universe (he's cybernetically-enhanced, after all), he is known for his green armor and reflective helmet. Will we see his face in the show or will Showtime stick to tradition and keep it hidden like Judge Dredd?
Kyle Killen (Awake) is handling writing duties for the series, picked mainly because he did not have a real background in science fiction. He's also serving as EP and showrunner. Killen's short-lived, Inception-y drama Awake was a fascinating character study of a man living two lives, so he certainly brings some character-driven chops.
“We made a conscious decision to hire a writer not known for sci-fi or big battle movies because that’s already baked into the Halo franchise and we will service that, but we also wanted to make sure we were getting underneath the armor of the Spartans to the human drama, so it felt like it belonged on Showtime," said Showtime's president of programming Gary Levine at TCA 2018. "Our hope is it will appeal to Halo fans and Showtime drama fans.”
Halo begins shooting in Europe this summer and could hit the airwaves as early as 2020.