Firstly, why player writing in Thaumnomicon about other thaumGuys, but (even if it's other multiplayer players) can't see any of them? Something like "Need for NPC".
And also, i was thinking about eldrich power, about emptyness and "empty" augment to gauntlet. Something like fanatism, power needs. Need for turn world into void. Using flux instead vis. Corruption, Darkness, warp and etc...
But also there should be some kind side. With glory and help of creator(XD).
From those two fraction become new idea, reputation. Like warp, but have two variant to grow. Killing eldrich and other doing kind things to world and aura cause reputation grow to "ordo" side. But if player learning dark arts, warping him self, make world suffer from flux killing thaumaturges and other kind living thaum creatures will make reputation low.
At high reputation any thaumaturge will follow player and help him. Giving presents, healing, defend. Also there should be some bonus for kind things...
BUT if one side like you, other hate you. Even if player doesn't have warped mind, there will be eldrich hunters. And they really hate kind players)
...
But there other side of coin. You can be bad guy and turn world's "ordo" into "perditio"))
Thaumaturges will hunt you, instead of helping you.
For player's bad things any eldrich thing will help you in something. Like thaumaturges at good reputation. Crimson cult pretty eldrich, so thay will like bad player too.
Also, to provide some prevention from killing your side mobs, there should be some code. For better comfort.
...
May be too many, too hard...
just some ideas about dark arts)