Evil build disguised

So, there is a campaign coming up soon, and its the generic "big bad evil is doing bad things" kind of thing. I dont know what types of characters are going to be in our party, but I spent the last month or two studying and building a lawful good paladin type of build.

Now that everyone i know in the campaign has heard me talk about this class or that class and talk about this divine feat and such, I want to build an evil character that is undetectable and appears to be a lawful good paladin.

So far i was thinking factotum and chameleon, changling as race.

any ideas?

Strength is nice, but my main focus is to be undetectable and able to betray my allies and never have them realize it.

Character level will be 20

What level are you starting at?

Character level will be 20

Vecna-Blooded Changling Cleric with the Southern Magician feat and a domain granting access to bluff as a class skill. Dedicate yourself to an Elder Evil for the perks (lots of bonus Vile Feats). Take the Persona Immersion feat and the Willing Deformity (Bonus Vile Feat) and Deformity [Madness] (Bonus Vile Feat). Congrats, you are now immune to all Mind Affecting effects, all Divination, can supply whatever false information you want if someone attempts a 3rd level or lower Divination on you (such as Detect Evil). Do typical Clericzilla stuff and stuff which makes you look like a Paladin (buff the crap out of yourself, prepare healing spells, etc).

You'll be undetectable outside of a Metacognition capable of beating Vecna's Caster Level targeting you, and can easily pass as a LG Paladin if you prepare the right spells.

Remember you have to spend a feat on quick draw for the lead sheets.

Are you trying to be undetectable in game, or ooc as well? Because ooc is a lot harder

I like Cleric of Pelor for this idea. Pelor the Burning Hate, that is ...

Im trying to do both, but i figure that just choosing my words wisely and discreetly passing things to the DM (and sitting next to him to avoid it being obvious) it should be possible to do OOC.