To unlock Takeo (Zombie Character) in Black Ops 4 Blackout, you need to play find the Letter to the Emperor, don’t use equipment and complete the match in the required place. If you fail to complete the character mission for any reason in one match, you need to find the Letter to the Emperor again in the next game again.
Takeo’s mission item can be found in typewriters across the map (Asylum, Lighthouse,…)
HOW TO FIND AND COLLECT LETTER TO THE EMPEROR
To make the Letter to the Emperor appear, interact (X/Square) with the typewriter in one of the following locations. The Letter now appears on the desk and can be picked up by interacting with it.