Help with boss character build?

[Zesty Gordita]

Currently going to be starting a campaign with some friends, it's the round robin with fallenibilis, and I'm currently making the big plot driving baddy.

He has a homebrew lich template, and due to story, he should be an arcane and divine caster. Also he's gestalted. At some point I came across a build in some forums that claimed to give 9/9/9 arcane, divine, and psionic. If someone knows what that build is, I feel like that would be perfect for this character, if not, I'm completely open to suggestions.
I know 20 Wizard//20 Cleric is an entirely solid option, I was just trying to see if there was anything more.... unique.

Also, we are allowing 20-22 levels for this build. And we are entirely aware of the potential power of this character and the danger of this (we've kind of given him 4-5 artifacts as it already stands...). All core and splash books are open for this character's build, and Eberron and Forgotten Realms on a case-by-case basis.

Thanks for all possible help!!

 

[RUMBLETiGER]

Google Found Me This.

I don't think it works unless your a Beholder.

Edit: Ok. Found This.

Or be an Illithid Savant.

 

[emoplato]

Currently going to be starting a campaign with some friends, it's the round robin with fallenibilis, and I'm currently making the big plot driving baddy.

He has a homebrew lich template, and due to story, he should be an arcane and divine caster. Also he's gestalted. At some point I came across a build in some forums that claimed to give 9/9/9 arcane, divine, and psionic. If someone knows what that build is, I feel like that would be perfect for this character, if not, I'm completely open to suggestions.
I know 20 Wizard//20 Cleric is an entirely solid option, I was just trying to see if there was anything more.... unique.

Also, we are allowing 20-22 levels for this build. And we are entirely aware of the potential power of this character and the danger of this (we've kind of given him 4-5 artifacts as it already stands...). All core and splash books are open for this character's build, and Eberron and Forgotten Realms on a case-by-case basis.

Thanks for all possible help!!

Well, what kind of BBEG where you thinking of? Having as many casting type options as possible always sound nice but keep in mind this is likely a character that is only going to come into actual play maybe twice. So, having a slew of common abilities of the three may not actually be as effective as something that can go above and beyond in its own category taking your party by surprise. I also don't see it as much of an issue of hyper-specialization when you are gestalting the guy anyway.