And by freelance, I meant on his own. Not alleiged to any one power.
Then what you wanted to say was 'Rogue Necromancer', and make sure that in a sentence you don't capitalise the rogue. Otherwise someone might think you're trying to multi-class. (Not that it's necessarily bad, but it easily becomes bad due to the difficulties of give/take in order to get both sides of such a deal to work.)
Also, sure, go ahead and establish your own Cult if you want. See how you go, maybe talk to Dala-Mufasa (The OP, I called her that and its stuck in my head now) about some ideas or plot points... Otherwise myself and a few other people on the server would be more than willing to sit down and have a good chat with ya.
Only 'issue' I personally have with your story however, now that you've allowed us a peek into the fleshy stuffs of it is simply 'He found a tome, it was about necromancy and embracing the shadow and he liked it.'
This is far too difficult right off the bat like that, because not even Kel'Thuzad, privy as he was to all the Kirin Tor's forbidden documents about Necromancy, picked it up until Ner'Zhul (Lich King) turned around and went "Hey guy! Yeah, yeah you in the hat! I like you. Want to learn from a pro? Subscription fee is only as expensive as your soul!" ... So you'd have to seriously build up your character progression through the relatively-unpracticed-by-civilized-folk art of Necromancy. My suggestion to help you? Duskwood is rife with the leave-behinds of previous dwellers who came from the dark places of the world... We've seen shadow-weilding Worgen, reanimated champions of the township, purple-hatted (And now Lich-ded) Necromancers, lots and lots and lots of skeletons... Basically a lot of things that have held at one point or another some semblance of 'power'...
Point i'm making? Use them. Not all of them, not only the uber-duper-super important ones that tie you in to the really powerful stuff (Because that treads the line of the Mary Sue) but instead... Why not the femur of a skeletal Shadow-caster? Or perhaps the physical heart of a Worgen? Get creative, and make use of physical 'prop' aids to help your guy create foci for his magic. That'll help make your single-handed rise to Necromancy far more believable, not to mention fun and gritty. Who knows? Maybe your character took the time out of his days to rob the graves of buried and -known- spell-weavers to pilfer their fingers and make a necklace to enchant with their residual spell-scents? Okay, maybe that last one is a tad left field... But who knows?
Harkening back to the idea of a guild based around your character, along with his servants and minions, you'd be better off only doing so with the people you trust the absolute most... Because it is basically having them put their characters almost entirely under your own characters, and in turn your OOC selfs will. That latter being something that becomes apparent later down the field and is hard to keep under close supervision, or 'wraps'.
Be careful with this idea, and trust it in the utmost to those who you know would be good for it, and who would be willing to join you in that endeavor.