Help with a build (mix of theme vs function)

[Rentirith]

Heyo playground people. im gonna be in a gestalt game where i will be playing a necropolitan sorcerer/paladin//dread necromancer. there are no alignments, so i just had to justify it in my backstory. My question is this: i intend to continue on nearly fully with the DN side to get the full benefit of the loads of undead HD i can have, maybe prestige-ing out nearly at the end, but what about with the sorc side? ive only got the two levels in paladin for the save bonuses. Some things to consider:

this will be set in faerun, so anything from those books is most likely allowed.
im looking for something with full casting, and utility.
my character thematically is from ancient netheril (was buried for a while) and worships Mystra (mystryl). Im looking at arcane devotee, but so far im not convinced.
Im probably not going for incantrix because it is just so overpowered (or can be). im preferring style over function.

That is all essentially.

[noob]

Can you replace the two levels of paladin by something else that will get you cha to saves and still progress your casting?(or take less levels to take)
(I do not know if that exists it might not)
For minionmancy you have already loads of undead with DN.
So I wonder what kind of thing utility means.
Maybe bardic music counts as utility and as a sorcerer you can get bardic music without slowing down casting-but you need two horrible feats for that)

[Gildedragon]

so your theme is... undead minionmancer?

In character how's they reconcile Paladin's mission with undead creation/[evil] descriptor spells (I know you said there's no alignment but still, working on the theme)? Why'd they (in character) dip Paladin?

[Rentirith]

so, essentially, im carrying the dread necro forward in order to have bigger undead under my control. i dont really care about having all the undead under my control (unless i say something like 'go do this thing here' and walk away). but if i have some undead dragons, or some undead with some oomf, then goodie.
Because in the game we wont have alignments, we can basically use in character intention to say whether or not something is good (but i assume we have to be truthful with the dm) or atleast in character. because im of the faith of Mystra, i would say that anything im trying to do, im doing for the good of the Weave, fighting the shadow weave, etc. So if i cast create undead, and make a mohrg, then im probably gonna say 'ok, you go and protect a library in secret' or something. Im also fairly fond of the DN features aside from the undead-ish stuff it gets.

for reasoning of why he is a paladin, in Netheril he was a member of the guard charged with protecting the Nether Scrolls. thus, he was gung-ho about mystrl.

[ShurikVch]

Note: Mystryl (http://forgottenrealms.wikia.com/wiki/Mystryl) was Chaotic Neutral - thus, Paladin of Slaughter (http://www.d20srd.org/srd/variant/classes/variantCharacterClasses.htm#paladinofSlaughterClas sFeatures) is an option

Also, if Dragon content is allowed, we may use Anti-Paladin (#312, Chaotic Evil), Anarch (#310, Chaotic Neutral), or Incarnate (#310, true Neutral)