Summoners and their Eidolons (Contains certain campaign spoilers)

[BlingerBunny]

Warning: Shackled City Spoilers

Here's the situation.
My friends and I are playing a Shackled City campaign in Pathfinder. We've just gotten into the second chapter and half the party was dominated by a Vampire and the cleric was Coup de Graced by a once fellow party member. I've been forced to make a new character, and I'm planning to build a Summoner.
My question is, since my Eidolon will be a quadruped, can it be dominated by a vampire, or will my summoners link with it override any attempt the bugger tries on my Eidolon. Considering the possibility that he's unable to dominate my Summoner.

[Darkwolf117]

From what I can tell, I think Eidolons count as Outsiders, so it should be safe from Dominate Person, Quadruped or not.

Something like Dominate Monster on the other hand, should affect it normally. As far as I know, the link with the summoner provides no particular benefit against that, although if it has Devotion, it would get a +4 morale bonus on its save.

Also, why is your summoner impervious to domination?