Now please don`t laugh but i seriously can`t make it out, why isn`t the Tzeench daermon called the Keeper of Secrets, since that`s what Tzeench promises, untold, forbbiden knowledge.
I know Tzeench is also known as the changer of ways, but in 40k fluff for the most part his bribe of choice is knowledge, not change. Change coms from serving any of the chaos gods, actually it generally comes from warp contact as a whole.
Look at Magnus and Ahriman and the Thousand Sons and some of the other primarches Tzeench sneakishly messed with. He used knowledge to corrupt them.
In fluff, the Tzeench cults that suply the thousand sons focus on relics and spells and arcane knowledge and psykers and that
Ahriman`s main purpose in life is getting to read everything within the Black Library (such a book worm).
Dunno, the more i look at it, the more i feel the title "Keeper of Secrets" better suits something tzeenchy
But then again, maybe the other names that they came up with for a slaaneshi demon were too.... slaaneshi to make the final cut