Yugoloths are summoned by evil wizards or priests to guard something of importance. Yugoloth guardians always defend their charge with great ferocity.
There are three types of yugoloth guardians -- least, lesser, and greater. The least and lesser yugoloth guardians vary in size and form, often being horned and frog-like (least) or ape- or boar-like (lesser). Greater yugoloth guardians always appear as gigantic, winged bears with ram horns protruding from their foreheads, and eagle talons for hands. Yugoloths guardian have the ability to speak all languages.
Yugoloth guardians can breath fire three times per day in a cone 30 feet long with a 10-foot base diameter. Damage depends upon the type of daemon breathing. Least and lesser yugoloths cause 3d6 and 5d6 points of damage, respectively, while greater yugoloths inflict 7d6 points per breath attack. A successful saving throw vs. breath weapon reduces damage by half. Yugoloth guardians never use their fire breath if the fire might damage whatever they are assigned to protect.
All yugoloth guardians are immune to charm, hold, sleep, polymorph, and fear spells. Lesser and greater yugoloths are also impervious to weapons with less than a +2 bonus. Many of these creatures are invulnerable to one or more additional forms of attack (e.g., sword, cold, fire, electricity).