Pathfinder 1E Animal companion and multiclassing?

[DarkLord Of DForce]

Hey. Was just curious about something...

We've got a few Druids in our current party. I'm not so
sure about them sometimes. Darned tree huggers.

Anyway, one of them has a great ape for an animal companion.

He multiclassed the ape (not his druid mind you) with a level of
fighter, now he says it has martial weapons proficiency and gave
it a big sword to hit with.

Is all that legal?

Thanks!

 

[Ezequielramone]

No, it's not. animal companions are not npc, cohort or followers. they don't get Xp. they advance as his master does since he is, in mechanical/resources way, part of the Druid. and only advances as the table in the druid's section says. advancing in other way, like gaining pc class levels is unbalanced and illegal.