The universe of Stellaris is as dark as you make it to be. This means that you can run a multicultural empire led by noble ideas, or a xenophobic one led by profit. Perhaps something in between? Zombies don't care in any case.
The Custodian team has the mandate to work on directives that come straight from the Game Director, Quality of Life changes they think would improve the game, and Community Requests that they wish to champion. They also have the right to pitch what is called “Passion Projects” for things they simply want to do.
One of these comes to life, sort of, in the 3.3 patch, as the Permanent Employment Megacorp civic.
A MegaCorp variant of Reanimators, this civic allows the construction of Posthumous Employment Centers, as well as the ability to reanimate Leviathans that the original Reanimators gained in the Lem update.
At the Posthumous Employment Center, carcasses bereft of consciousness can find new purpose and a new opportunity to pay off their debts. The Reassigner jobs from the P.E.C. provide organic pop assembly of mortally impaired, well, Zombies.
Zombies cannot produce leaders, have no happiness, are infertile, and can only work Worker strata jobs… But on the bright side, they don’t have any upkeep and won’t ask for any more raises. There are a few more interesting interactions developers leave for us to find on our own during gameplay.
If there are any Warhammer 40k fans playing Stellaris, a quote may come to their mind: " Even in death I still serve."