I recently got my hands on nearly 6,000 points of Grey Knights for quite cheap, all built, not so much on the painted part. My only problem is that I don't really like the background for the Grey Knights, like... At all. Though the models themselves are some of my favorites.
*Well-thought-out-in-game-backstory* wise I've always been more partial to Chaos, and as I was reading about some more of the Grey Knights story, I realized there may be a way to achieve the Chaos theme, while still using the Grey Knights models/rules.
That opportunity comes in the form of Mr.Crowe. He wields a blade rumored to give extreme power, however it is all but promised that using that power will corrupt the person who opens themselves up to it. Crowe has vowed to use this sword, but never tap it's power, despite being "incorruptible" it's not worth the risk, and even without tapping into the power, his struggle against the sword is not easy. The entry ends saying that he will remain devout and pure "until the day of his death."
So then I propose that Tzeentch planned all along to have the blade land in the hands of the symbol of imperial purity, and in a battle between Chaos and the Grey Knights Crowe was struck down, in his moment of weakness, the blade still in his hand seized this opportunity to push into his mind and at the moment of death, he was resurrected as a servant of Chaos. The power granted by the sword is an army designed by the psyche of the holder of the blade, and fueled by the demonic powers of the four gods. While the army appears to be Grey Knights in armor design, some things have changed, such as banners devoted to the dark gods.
I am also planning to paint them in four different color schemes, I haven't yet decided whether or not to separate it by squad or by equipment type. I am currently leaning towards equipment type, with Tzeentch for special weapons and basic swords (+1 invulnerable save), Slaanesh for Halberds as they give bonus initiative, Khorne for Falchions, with their +1 attack, and Nurgle for Apothecaries and Hammers, for feel no pain, and loss of initiative. For the colors themselves I aim to use the Nurgle and Tzeentch colors from the recent How To Paint Chaos Warriors Forsaken. For Slaanesh I want to use Creme colored polished looking armor with deep purple details to contrast, and lastly for Khorne I will use the magma scheme I used for the armor in the picture that I can't post here, so it's on Dakka: [url]http://www.dakkadakka.com/dakkaforum/posts/list/0/506508.page#5268255[/url]
Any ideas to expand this would be welcome, as well as criticism, I haven't started yet so now is the time to talk about it!