Video game where you work for a demon

In Cult of the Lamb you found a cult dedicated to worshipping a demon who saved your life.

In Cuphead you do Satan's bidding to expunge your gambling debt.

All three Baldurs Gate games can have this to some degree. They are RPGs so you can reject working for the demons but you don't have to.

The Darkness, it is an Xbox 360 game.

But you can it pretty much on most consoles these days aswell as PC.

Genuinely one of the best games ever.

Especially The Darkness's raspy corroded voice... Here is a link to a video with it's voice.

Devil may cry

Does Shadow of the Colossus count? 😅

Dungeon Keeper

The Darkness...old PS3 game

Bit of a spoiler, but Baldur's Gate 3 has some opportunities for that.

I guess Cuphead would fit?

Spawn Armageddon but its an OG Xbox game.

You can work for a demon in dark souls, Baldur's gate 3, and I think dragon age too

Overlord?

Skyrim

I don't know what exactly you're looking for, but here are some I can think of :

Chapter 3 of a hat in time revolve around you being forced into various contracts with an powerful shady ghost

The birthing of Isaac have deal with Satan as an game mechanic

Dokkapon kingdom have a special event where, if you're in last for a long while, you can go to an specific space and give all your possession to a demon so he make you extremely powerful for a while

The plot of cuphead revolve around you being forced to collect souls for the devil

Zelda breath of the wild and tear of the kingdom both have demonic statue where you can either sell or buy heart or stamina containers

There are probably many other exemple, but those are the ones I remember right now.

Afterparty

Have a Nice Death

Doesn't Bayonetta work for a demon? The black man in the bar?

The Darkness 1 and 2

Hades

possibly The Elder Scrolls III: Morrowind, with Lord Vivec, but i haven't completed it yet.

In the Kid Icarus games you play as a servant to the goddess of light. Link in the legend of Zelda games is pretty much a servant of the gods as well.

Tecmo’s Deception for the PS1. Interesting concept where you take out NPCs using traps and work to bring back the devil.

Tecmo’s Deception

Tecmo’s Deception on PS1. The sole objective of the game is to resurrect Satan

For a fun kinda twist on what you said, The Messenger

Is this some fetish thing 🤣

The first god of war

Conan Exiles

The Witcher 3 Hearts of Stone

Hell Pie. You habe to collect ingredients gir a pie that will be fed to Satan.

that's Black and White 1/2 or Dungeon Keeper?

Infernal 2007

Tekken

Irl corporate politicians