Having made a complete study of summoning creatures, you are able to call extremely powerful servants.
Benefit: By performing an hour-long ritual, you can summon a single creature of the outsider type whose CR is 9 or less. This creature obeys your commands to the best of its ability. The creature returns to its home plane after 1d4 hours or when it is slain, whichever comes first. To complete the ritual, you must expend 1000 gp in material components and must also sacrifice some of your own blood, which causes you to suffer 5d6 points of bleed damage for 1d4+2 rounds. You may never summon more than one creature a day with this ability.