The gods are created by people. Khorne was anger, Tzeentch was deception and nurgle was the disease. Unlike the other 3 slaneesh was not made prodominantly by humanity but by the desire of eldar, that is why he represents desire. But because of the timeless nature of the warp Khorne was the first to be awoken but is no older than the others, they are all the same age. In a way they have both always existed but never existed. And Gore if those scribe daemon things ever record every spell their is then the staff could be reforged gaining tzeentch back his power. And for me the most powerful is Tzeentch because before he battles another gods he tricks them into fighting each other giving him the upper hand
Do not disallusion yourself brothers, today we die, our bodies broken and our souls shattered, we will be remembered as corpses on a battlefield.Raise hell my brothers for one day our great Father will hear of our struggle, and he will be honoured to call us his Sons. In death our Glory shall become eternal.' Karik Farron, 1st Lord of the Dark Scorchers at the Fall of Kempar.
'like a blind man in a dark room trying to find a black cat that isn't there'-imntdead