Greater Planar Binding

This spell can be used similarly to a binding spell, but you only have one choice: to call and capture some elementals or outsiders (up to 24 HD worth) to act as guardians or servants in your stronghold.

Creatures called through greater planar binding have three ways to escape: by using their spell resistance, by using dimensional travel to escape, or by succeeding at a Charisma check. Smart spellcasters use dimensional anchor to prevent dimensional travel and use a calling diagram and the relevant magic circle (see the Conjuration section of Chapter 10 of the Player’s Handbook) to negate the creature’s spell resistance and make the Charisma check harder. The price below assumes you have hired a spellcaster to cast all three and prepare a calling diagram.

Most spellcasters use greater planar binding to make a deal with the called creatures, using their predicament as leverage. Of course, nothing says you have to let the creatures go once you have your hands on them. You can set them up in a public cage as a warning to trespassers if you like, a display of your character’s power.

You can use them as part of a trap. Set up the spell so that the creatures are bound in some hidden part of your stronghold. Then set up a greater glyph right near the area and store a greater dispelling spell inside it. When an intruder enters, the glyph goes off and, with any luck, frees the captives, a group of creatures that are not likely to be in a very good mood. Of course, you risk the possibility that the glyph might not go off, but the mere presence of the elementals or outsiders may be enough to scare off less than courageous intruders.

The real danger here is that the captured creatures can try to break free once per day. Eventually, they will succeed. As such, many stronghold owners only set up such systems when they expect imminent invasion. This tactic serves as insurance: If you survive the larger battle, you can set the creatures free without prejudice. If you die, the creatures will eventually get free to plague the area.

Casting: 1,630 gp (Wiz15) or 1,710 gp (Sor16)