To unlock IX Shaw (Zombie Character) in Black Ops 4 Blackout, you need to play find the Ritual Bowl, use 5 perks and complete the match in the required placement (Top 30 in Solo). If you fail to complete the character mission for any reason in one match, you need to find the IX Shaw’s Steel Bracer in the next game again.
IX Shaw’s mission item can be found as a zombie drop in active zombie locations.
This Character mission seems to be bugged as of this video (Dec. 11, 2018). Even After completing the requirements, IX Shaw does not unlock.
Try to drop the Ritual Bowl once you’re in the top 30 and pick it up again.
HOW TO GET THE RITUAL BOWL
This mission item can be found by killing zombies in one of their dedicated map locations. When the match starts look for the light beams, this indicates where you will find zombies.
Once you got the bowl, simply use 5 perks in total during the match and finish the match in the required placement.