Two lycanthropic questions:

[psychognome]

1st Question:
What if a demon and a natural lycanthrope werewolf... you know... did it?
I'm seeing something like a half-fiend/half-werewolf, a creature that'll be able to change shape and that would have all the modifiers from the half-fiend template in all forms. This could be very nasty, as the said werewolf would have two claw attacks to support her bite attack in her wolf and hybrid forms. Add into that spell-like abilities and wings, and you'll have quite a nice little fluffy creature...
2nd Question:
Could a lycanthrope, instead of advancing by character class, take animal Hit Die? Would this increase his size in all forms or just his animal and hybrid forms? My take on this is that a werewolf that advances to 4 animal Hit Dice would gain the benefits and flaws of the size increase in his wolf and hybrid forms only, and he'd just be a normal creature in his natural form.
So, whaddya think?

[Krishnath]

Let's see if I can clear things up a bit.

1st: Just take the base humanoid (say a human, elf, dwarf or whatever) add first the werewolf template, and then the half-fiend template, remember to make the changes from the second template in both forms, it is possible for a Half-Fiend Werewolf to have wings in either form, but not both, although this is rare (roll for each form seperatly).

2, That is pretty much up to the DM, but I usually change the animal-forms size as the N/PC advances in class levels, but usually at half speed (werecritter has to have twice the HD required for a size change), but that's probably just me.

I hope I was of assistance

[ragnarok]

to the first question I go with Krishnaths answer.
For the second:
The MM says, regardless of form: If you want HP or HD take whatever produces the greater total.
So if you have an 1st lvl comoner, who had been infected by a Werebear(6hd) and he could advance as such, you would now have an 1st level comoner with 7hitdice and a bunch of HP but not so great skills, etc.