- Location
- The Cosmos
Killing (at least one of) the Chaos Gods is possible - Drach'nyen could, for example, if someone capable of powering it enough managed to fight their way into a god's Place of Power and survive long enough to actually stab the God in question. Which, granted, is a fairly high bar.
Some of the saner (or possibly least sane, depending on your perspective) Cryptechs could probably come up with something, too. Even if that something was "steal a Blackstone Fortress, reverse engineer the main gun, also Voidcannons, then build an even bigger one, invade Cormorragh, and shoot the thing through Khane's Gate until everything on the other side stops moving."
Kademon with the Fulgerite in hand could probably at least do in Slaanesh, if he could get a solid hit in, and wasn't exhausted fighting a couple hundred Daemonic Legions to have the opportunity first.
Now pretty much all of these and other, similar circumstances are generally far easier said than done, but it is possible to kill even a God of Chaos.
Just
Very, very difficult.
That's an interesting take on the chaos gods. At risk going off-topic I was always under the impression that the gods of chaos were less gods and more forces of nature. While there is a big mean daemon on a throne in each of the gods respective realms that calls itself Slaanesh, Khorne, or Nurgle even if you killed them another daemon calling themselves that name would eventually pop up and take its place. Because 'Slaanesh' or 'Nurgle' aren't singular daemons, they're all of their servants, they're their realms, and to a small degree they are the emotions they're born from. You can't 'kill' them anymore than you could kill gravity or the concept of thermodynamics.
Though knowing that they are in fact unfathomably powerful daemons on a throne makes them slightly more manageable for the purposes of the quest. Still nigh impossible but better than what I thought.