Bind Spirit: A spirit caller may seal pacts with otherworldly entities known as spirits. In order to summon a spirit, the spirit caller must learn the spirit’s ceremony, constellation, personality, and seal by completing its four Knowledge Tasks; see Researching the Spirit for more information on this process. A spirit caller begins play having completed all four Knowledge Tasks for one 1st-level spirit of his choice that belongs to one of his chosen constellations (see tunneled summoning below).
Each day, a spirit caller may bind one spirit to his soul using pact magic; see Performing a Pact Ritual. This spirit’s level may not exceed the spirit caller’s maximum spirit level, which is limited to 1st-level spirits at 1st level. At 4th level and every three summoner levels thereafter, the spirit caller’s maximum spirit level increases by 1, to a maximum of 6th-level spirits at 16th level.
A spirit caller’s binder level is equal to his level. The DC to resist a spirit caller’s supernatural powers is equal to 10 + 1/2 the spirit caller’s binder level + the spirit caller’s Charisma modifier.
This ability replaces eidolon.
Tunneled Summoning: A spirit caller may only seal pacts with spirits that grant an animal companion, eidolon, familiar, or mount as a vestigial companion and he must select a spirit’s vestigial bond ability whenever he seals a pact with such a spirit. This restriction applies even if you multiclass into a different class with the bind spirit class feature. While he is showing a bound spirit’s physical sign, the spirit caller treats his vestigial companion as his eidolon for all feats, spells, and class abilities (such as shield ally or rejuvenate eidolon) and it is considered both an occult creature and a summoned creature for the purpose of determining how spells and other effects affect it. The spirit caller stops treating his vestigial companion as his eidolon while his physical sign is suppressed or after it is killed.
Twist Companion (Su): At 10th level, when a spirit caller seals a good pact with a spirit, he can choose to grant that spirit’s vestigial companion a number of evolution points equal to half his level, treating the vestigial companion as though it had a base form most appropriate for its kind. These evolution points stack with those gained from the Evolve Vestigial Companion feat†.
This ability replaces aspect.
Improved Twist Companion (Su): At 18th level, a spirit caller grants his vestigial companion evolution points regardless of whether or not his pact is a good pact or a poor pact.
This ability replaces greater aspect.
Twin Spirit (Su): At 20th level, a spirit caller forges a true connection with his vestigial companion. As a standard action, the spirit caller can assume the shape of his current vestigial companion, copying all of its abilities and evolutions (from the twist companion class feature). His Strength, Dexterity, and Constitution scores change to match the base scores of his vestigial companion. He can choose to have any gear that he carries become absorbed by his new form, as with spells from the polymorph subschool. Items with continuous effects continue to function while absorbed in this way. The spirit caller loses his natural attacks and all racial traits (except bonus feats, skills, and languages) in favor of the abilities granted by his vestigial companion. The spirit caller retains all of his class features. The spirit caller can keep this form for a number of minutes per day equal to his summoner level. These minutes don’t need to be consecutive, but they must be spent in 1-minute increments. The spirit caller can end this effect as a free action.
This ability alters twin eidolon.