A shield guardian when fashioned is keyed to a particular amulet. Henceforth, it regards the wearer of that amulet to be its master, protecting and following that person everywhere (unless specifically commanded not to do so).

Combat

Spell Storing (Sp): The shield guardian can store one spell of 4th level or lower that is cast into it by another creature. It "casts" this spell when commanded or when a predetermined situation arises. Once this is used, it can store another spell (or the same spell).

Construct: Immune to mind-influencing effects, poison, disease, and similar effects. Not subject to critical hits, subdual damage, ability damage, energy drain, or death from massive damage.

Shield Other (Sp): The wearer of the keyed amulet can activate this defensive ability if within 100 feet of the shield guardian. Just as the spell of the same name, this transfers to the guardian half the damage that would be dealt to the amulet wearer (this ability does not provide the spell's AC or save bonuses, but see below).

Guard (Ex): The shield guardian moves swiftly to defend the amulet wearer by its side, blocking blows and disrupting foes. All attacks against the amulet wearer suffer a -2 deflection penalty.

Find Master (Su): No matter the distance, as long as they are on the same plane, the shield guardian can find the amulet wearer (or just the amulet, if it is removed after the guardian is called).

Construction

A shield guardian costs 100,000 gp to create. This cost includes the construct's physical body, the keyed amulet, and all the materials and spell components that are consumed or become a permanent part of them. This cost includes 1,000 gp for the body and 500 gp for the amulet.

Creating the body requires a successful Profession (engineering) or Craft (sculpture) check (DC 16).

The second requirement is creating the keyed amulet from bronze, which requires a successful Craft (metalworking) check (DC 12).

After the body and amulet are fashioned, the creature must be animated through an extended magical ritual that requires a week to complete. Understanding the ritual requires a 12th-level character with the Craft Wondrous Item feat. The creator must labor for at least 8 hours each day in a specially prepared laboratory or workroom. The chamber is similar to both an alchemist's laboratory and a smithy and costs 1,000 gp to establish.

When not working on the ritual, the character must rest and can perform no other activities except eating, sleeping, or talking. If personally constructing the creature's body, the creator can perform the building and ritual together. If the creator misses a day of the ritual, the process fails and must be started again. Money spent is lost, but XP spent are not. The shield guardian's body can be reused, as can the chamber.

Completing the ritual drains 2,000 XP from the creator and requires limited wish, locate object, make whole, shield, and shield other, which must be cast on the final day of the ritual. The creator must cast the spells personally, but they can come from outside sources, such as scrolls.

Amulet

If the keyed amulet is destroyed, the guardian ceases to function until a new one is created. If the wearer dies but the amulet is intact, the shield guardian carries out the last command given.