Chaos Marines wielding Grey Knights equipment?

[MegaVolt87]

 

If a GK is binding part of their soul to a weapon, its gonna be hostile to someone corrupted- like a demon weapon. Throne mechaicum is hostile to the weak/ evil for Imperial Knights, souls of past pilots too. Same thing. Someone warp touched, god marked, chosen etc wold be safer with binding demons to wargear, than risking fighting a pure soul in a GK weapon to subvert it. GK weapon is basically an Imperial demon weapon that is hostile to chaos instead. 

 

As opposed to Chaos daemon weapons, that are famously friendly to their wielders.

I'd assume it's far easier to corrupt something like this, and far less risky, than to bind an entirely new daemon into a different weapon.

 

 

A demon is wicked as is the one who would use one. A demon would only betray you at worst half the time because you have plenty in common. A pure soul would be constantly trying to destroy you, very likely do its best to resist its leaving/ destruction to kill you. You have more in common cause with a demon to make a deal/ understanding or even be the master as you are god marked, chosen, blessed etc. Its safer for evil to truck with evil. Word Bearers don't even use geller fields anymore when they warp travel such is their favor and power with the warp/ demons. 

[Lord_Caerolion]

A daemon hates being bound, they constantly fight against their bindings. Even a daemon weapon granted by the Gods themselves isn't happy being there, and will do everything in its power to either be released or to find a more suitable host, only kept in place by the willpower of its master. The daemon might agree to serve, but it will still look for the slightest moment of weakness in which it can strike. The same goes for the Word Bearers and their daemonic gellar-equivalent. They don't get that by asking pretty please and saying the Gods like them. They get it by binding daemons to their will, the more powerful the better, and forcing them to do their bidding. The safety of the ship is granted by having bigger, scarier daemons bound to defend it. Just have a look at the Ragged Knight in Talon of Horus for how treacherous even a bound daemon is for even a Chaos Sorceror specializing in daemon-binding.

Daemons might be on the same side, but they're certainly not friendly, and are absolutely never "safe".

 

A soul-bound Nemesis Weapon, on the other hand, has a link to a portion of a Grey Knights soul. It's not the full thing, it's enough to establish a sympathetic psychic link between wielder and weapon. Simple long-term exposure to Chaos taint should be enough to "cleanse" that, at worst you might have to banish it, which won't run any of the usual risks of an angry daemon suddenly appearing and attacking like a normal banishment would.

[BLACK BLΠFLY]

Abbadon feeds Drachyen ham sammiches just saying .

[Lord_Caerolion]

Rumour has it that Khornate daemon weapons can be fed pizza with pineapple, due to the sheer rage it inspires.

[Brother-serpent Tylydox]

There was a short story about how Erebus allowed to get himself captured at a Penal Planet just so he could drew in an Inquisitor to interrogate him.  It turned out Erebus needed the Inquisitor for the knowledge about the subsector.  The Inquisitor's bodyguards were the Grey Knights who all got killed when the Erebus' main force showed up to free Erebus from the jail and capture the Inquisitor.  I bet some of the Grey Knights halberds went straight to the Word Bearer's armory as a trophy.