any tips on how to play a build like this and what skills should be used

Well what kinda dark mage are we talking? Destruction mage? Conjuration Mage? Or possibly combination of the two?

i thought of a offensive mage,conjuration and possibly one school of destruction and id like some one handed and sneak thrown in there.

im not sure if theres a archetype for something like this

Hmm, defiantly destruction skills. Conjuration and raising the dead skills will help. I recommend the ritual stone I think its called, raises every dead corpse around you.

OP- If you are on PC you need to check out the mod called "Undeath." This mod adds a fantastic quest where you can ultimately become a lich! Even if you don't want to be a lich though, it still adds 2 player homes perfectly suited for dark/evil characters.

You always recommend that mod huh? xD IIRC you did to me too. Haven't downloaded it yet. Now that I'm busy with my Chaotic(good/evil) Archetype mage Altmer I will.

Thanks!

Oh it's a great mod and extremely well-made! I only have minor complaints about it but love it nonetheless. Also, you can playthrough the mod a a "good" character and simply destroy/thwart the necromancer plans.

im on console and my character would be i would say neutral more so then evil

Destruction and the "questionable" side of Conjuration.