Advancing a Crypt Thing

[Eye Tyrant]

So I finally picked up the Fiend Folio and want to use the Crypt Thing immediately. Only catch is that my group consists of 5 11th level PCs and this thing is only a CR: 3...

So advance this thing right? But I don't want to just give him more HP and better attacks etc... Can I give him PC levels? It states that the Crypt Thing is "built", but it has a significant Int...

I realize that I can do whatever the heck I want, but I have yet to actually make my own super duper monster. Everything I've used to date has been staight outta the book or generated from some other source that was not me.

I want to have said Crypt Thing guarding a gate to Undermountain. This gate is going to be located in an ancient dwarven catacombs and leads to the Lost Level of Undermountain... Of course there will have to be other "guardians"...

Any help out there?

 

[Talmun]

So I finally picked up the Fiend Folio and want to use the Crypt Thing immediately. Only catch is that my group consists of 5 11th level PCs and this thing is only a CR: 3...

Any help out there?

I'd either advance the crap out of it's HD, add a template, or both.

I know there aren’t many templates you can add to a creature that's already undead (Spellstiched...), but that doesn't mean you can't come up with one.

Alternatively, you could create a Greater Crypt Thing from scratch using the FF version as a model.

Another alternative to that is to go ahead and give it class levels.

 

[Altamont Ravenard]

Crypt Thing Abjurer9 (it's there to protect, isn't it?) of course you'd have to boost his Int considerably

Crypt Thing Monk9 (to dispose of intruders in a non-leathal manner)

Crypt Thing Enchanter9 "my friends, you do not wish to enter this place. I am doing you a favor by protecting you from this dangerous place" (Int boost needed also)

(I gave them 9 levels so as to have a CR12, which would seem appropriate for your party)

AR

 

[der_kluge]

Do whatever you want. It's your game.

Personally, I would advance it to the maximum HD allowed before it changes to a different size category. (Hey, I follow *some* rules)

And then you could just stack on levels of fighter. No reason why you couldn't do that.