Could I get Help Building a Fetchling Arcanist

[Nosta]

I need a Back up Character for my friends Game and I want to play with shadow Magic. However I've never played a full caster and I need a lot of advice.

Its a 20 point Buy game and i know INT and cha are both important but i am not sure what my stats should look like

I also need to know what traits i should take
and also what Feats i should take and what exploits would be best to maximized my effectiveness as a shadow mage

Right now the party is level (8) and I know we'll Make it to level (16) I just want to flush out this build and have it ready in case my current character kicks the bucket

[Florian]

Is LE a viable alignment option?

[Nosta]

Is LE a viable alignment option?

yes. it is. I actually think that would be fun

[Florian]

Ah, well, welcome to Nidal, all praise Zon-Kuthon!

Ok, some rough hints:

Race: You'll want the Shadow Magic ART on your Fetchling.
Traits: Vile Domain - Darkness
PrC: Umbral Court Agent for the upgraded Tenebrous Magic
Feats: Ancient Draconic (For use with Shadow Enchantment), Cunning Casting (as you'll already be going for Deceitful), Spell Focus (Illusion)/Solid Shadows/Varisian Tattoo (Illusion), Spell Penetration.
Equipment: Mesmerizing Tattoo, bunch of Nethys Dagger and Chromatic Sand, Rod of the Wayang, bunch of Varisian Idols (Idols, Ragario).