He’s developing the series based on the work by Hajime Segawa that has seen anime adaptation that Funimation licensed and released previously.
The Hollywood Reporter recently revealed that a live-action TV adaptation of Ga-Rei-Zero is in the works with Craig Kyle talking about it at Japan Content Showcase today.
That set was originally planned for a spring 2019 debut but has now been formally scheduled for a June 26th, 2019 arrival date.