Battle Companion

Feats

At 10th level, you can summon a battle companion. This ability functions as summon monster IV with a duration of 1 minute, but can only summon demons. This ability can summon only one creature, regardless of the list used. For every 2 levels beyond 10th, the level of the summon monster spell increases by 1 (to a maximum of summon monster IX at 20th level).