From the druid's Nature Bond ability:
... If a character receives an animal companion from more than one source, her effective druid levels stack for the purposes of determining the statistics and abilities of the companion. ...
But what if one of my sources has restrictions on animal types or gives additional bonuses to the companion?
Suppose I have a level 10 druid with a giant centipede companion. In a fit of madness, I decide to multiclass into oracle and take the Bonded Mount revelation from the Nature mystery:
You gain the service of an unusually intelligent, strong, and loyal mount. The creature must be one that you are capable of riding and is suitable as a mount. A Medium oracle can select a camel or a horse. A Small oracle can select a pony or wolf, but can also select a boar or a dog if she is at least 4th level. This mount functions as a druid’s animal companion, using your oracle level as your effective druid level. Bonded mounts have an Intelligence score of at least 6.
- Does my giant centipede continue advancing as I gain levels in oracle, even though it's not on the list of animal types an oracle could select?
- Does my giant centipede's intelligence immediately increase to 6 when I gain the revelation?
- If the giant centipede isn't compatible with the oracle animal companion feature, what if I chose a horse as my druid companion? Would its intelligence immediately increase to 6 when I gained the revelation?