Shield guardian

Created by spellcasters and controlled by means of a special amulet, Shield Guardians are predominantly defensive in combat, protecting their masters with unswerving loyalty.

Special abilities
A shield golem regenerates 5 HP per round as well as possessing the usual construct immunities to critical hits, death magic, disease, level drain, ability drain, mind-affecting spells, paralysis, poison, and sneak attacks. It is furthermore immune to all spells of level 4 or lower.

Shield golems have the spell-like ability to create fireballs, magic missiles, and melf's acid arrows twice per day as level 6 casters.