Fluff wise, what happens to Stormcast Eternals mutated by Tzeentch spells?

[EntMan]

I am planning a Tzeentch army, mainly to satisfy my urge to kitbash and mutation-mod models.

I am planning to have a unit of Tzaangors made up of prior enemies who have been blessed  by the Boon of Mutation spell in previous battles and also a Chaos Spawn or two who used to be other things before experiencing a Bolt of Change spell. This should give me fluff free reign to kitbash various models from other factions with mutations (yay greenstuff!) and include then in my Tzeetch army.

But this got me thinking, what happens fluffwise to a Stormcast who has been blessed by a Tzeetch spell to become either a Tzaangor or a Chaos Spawn? Under normal circumstances a defeated Stormcast gets zapped back home and re-forged. But if they are turned into a mutant what happpens? Is their soul reutuned to Sigmar while some chaos spirit controls their mutated body? Or if they are stuck as the mutuant then when they die as a mutant do then then return to Sigmar? Or Can their physical body even last long as a mutant or would their corrupted body be quickly reclaimed by Sigmar and teleported back for cleansing and re-forging?

Is anyhting of this covered in any lore, stories or other fluff?

[Baron Klatz]

It happened in "Warstorm" when a Tzeentch wizard unleashed all his magic to slow down their advance on his fortress in Chamon. Some mutated, some broke apart into the native clockwork fish, one split into black & white daemon halves and attacked eachother while the leader turned into a living statue of Sigmarite and kept fighting until the end. He and the others were reforged into pure bodies at the end to give vital information.

If they're not destroyed by battle to send them back then the affected are zapped back up to Azyr and purified or their souls reforged into a new body.

The mutation would only stick if they're somewhere like the Eight-points where the God-king can't reach them but even then their soul (which is infused with Sigmar's essence, extremely chaos resistant) is just trapped in the body until it can be removed from the Chaos sub-realm blocking it.(There's Stormcast souls trapped in a lot of chaos places, like Dorghar's stomach, that Sigmaron keeps planning to one day save if they get the opportunity)

Edited January 10, 2021 by Baron Klatz

[Kramer]

I trust @Baron Klatz recollection on this one. 
but i wills at, GW is inventing reason for stormcast souls not to escape left right and centre. 
so don’t let it stand in the way of cool conversion. 
also show said conversion 😅

[Baron Klatz]

Oh yeah, the Mortal Realms and numerous gods are vast enough for any abnormalities to happen, so go crazy.

Heck, in that very story(the second ever AoS book) that Tzeentchian's fortress had giant skulls he embedded in the sides to suck the souls out of the nearby town of Chamonians. And to the Stormcasts concern when they died their reforging lightning arced right into the skulls too where it was using them as batteries until they were destroyed by the army and released the souls.

If you need justification just say the Stormcast's souls were captured in such a manner and a greater daemon/powerful shaman entrapped them in those bodies under a convergence of chaos realm energy so they're constantly got a ensorcelled barrier around them to stop the Azyr lightning (maybe use that to explain a greater Save value or if they're your elites like Ogroids or even something for the Anvil of Apotheosis).

Best of luck with your army too!

Edited January 10, 2021 by Baron Klatz

[NinthMusketeer]

If they were turned to a spawn their soul is still in the spawn, but they don't have any control. There's a great scene from... somewhere, don't remember but it has a Stormcast getting turned into a spawn which then turns and attacks the other members of his unit and all the while they can hear a garbled voice coming from its mouths begging "kill me". They do, and his soul gets zapped up.

 

Remember kids, Tzeentch is a hell of a drug.

Edited January 11, 2021 by NinthMusketeer

[EntMan]

Thanks everyone, great answers as usual! I will try and remember to post pics when I've done the models.