Lower Levels...
Advanced Aranea at CR 5. DAAAAAAAAAAYUM. Shapechanging, huge natural armor, giant scores, 20 Charisma casting as a 5th level sorcerer, 5d10 instead of 5d6 plus a 18 Constitution, the thing is just a monster.
Throw in all the skills it gets for an 18 Intelligence (something that makes sense for a mastermind!) and it all just comes together beautifully.
Basically anything that casts at its CR or higher can be given an Advanced template or a level to be a better caster and get the Elite Array and just be a brutal opponent.
Any fave BBEG monster candidates?
