Celestial Appearance (Ex): The eidolon appears as a celestial creature and manifests some of the abilities of a celestial. Spells and effects that target creatures with the good subtype or have specific effects against such creatures affect the eidolon as if it were a celestial. The eidolon gains a +2 bonus on saves against disease, petrification, poison, and electricity spells and effects. It also gains spell resistance equal to 5 + its HD against spells with the evil descriptor.

At 7th level, by spending 2 additional evolution points, this bonus on saves is increased to +4 and the spell resistance is extended to affect any spells and effects from evil creatures.

At 12th level, by spending 2 additional evolution points, this protection is increased to immunity
against these attacks and the spell resistance is increased to 11 + its HD (the summoner must pay for
the 7th-level upgrade before paying for this 12th-level upgrade). The summoner must be good-aligned to select this evolution.