Obligation Gems
These rare magical items are created by summoners as an emergency, last resort method of self defense. The gems that these are made from vary, but they always have runes inscribed on all sides. These runes are typically written in draconic, and detail the terms of the agreement.
These gems are bound to a specific creature on another plane of existence, one that the summoner has made a pact with prior to using the gem. The summoner must still bargain with the creature, but he pays in advance. In exchange, the gem can be shattered (a free action) to summon the being linked to it is summoned to that spot. The creature fights for whoever broke the gem, and stays for exactly one combat. If the gem was shattered by anyone but the summoner who made the bargain, the creature departs immediately after completing its obligation. The runes on the gem do not specify what creature it summons. It is common the person who created the gem to color code them, binding a specific type of creature with a specific type of gem.
There are three types of Obligation Gems, one for Lesser Planar Ally, one for Planar Ally and one for Greater Planar Ally. These are unable to tell apart physically. The prices for each gem do not take into account the cost of the deal made with the summoned creature. These items are very rarely for sale, and any who are have usually been taken from dead summoners. Most are unwilling to sell their pacts, mainly because they cannot make another deal with the same creature until the first one is completed.
Faint/Moderate/Strong Obligation. CL 7/11/15; Craft Wondrous Item, Lesser Planar Ally/Planar Ally/Greater Planar Ally. Price: 700 GP/1650 GP/3000 GP.