The Aranea in the bestiary 2 says that it casts as a 5th level sorcerer but doesn't have a bloodline or get bloodline special abilities. If I advance an aranea by adding sorcerer levels the caster level should stack (adding 5 sorcerer levels should make the aranea cast as a 10th level sorcerer).
now if I advance any given creature by adding sorcerer levels it would gain a bloodline just like any other sorcerer. I assume that by adding additional sorcerer levels to the aranea it should get a bloodline and bloodline abilities as well correct?
If so, should its bloodline abilities be based only upon the additional sorcerer levels or its total casting level?
If all aranea are magically inclined and can cast spells as though a level 5 sorcerer, and your advanced one happens to be particularly gifted with sorcery then I would treat it's bloodline as that of the levels of sorcerer it has. So as a 5th level sorcerer. Arcane would make sense.
Thanks for the response.