Spirit (Su)
Source: Advanced Class Guide, p. 123
Replaces: This ability replaces the summon monster spell-like ability.
A spirit summoner forms a mystical bond with one spirit from the shaman class (see page 37). He gains the spirit ability of that spirit and uses his summoner level as his shaman level for determining its effects. The spirit summoner can select spells granted by that spirit as summoner spells known, using the shaman level of the spell as the summoner spell level. The summoner cannot select spirit spells of 7th level or higher.
At 9th level, the summoner gains the abilities listed in the greater version of his selected spirit.
At 17th level, the summoner gains the abilities listed for the true version of his selected spirit.
This ability replaces the summon monster spell-like ability. Eidolon: At 1st level, a spirit summoner begins play with a powerful outsider called an eidolon. The eidolon’s form and abilities must be appropriate to his chosen spirit, at the GM’s discretion—for example, a summoner with the flame spirit cannot have an eidolon with ice or water abilities, a summoner with a heavens spirit cannot have a fiend-like eidolon, and so on. The summoner can use temporary effects (such as evolution surge) to alter the eidolon into an inappropriate form, but cannot use permanent effects (such as transmogrify) to do so. This ability alters the eidolon class feature.