I wrote this up a long while back after rereading Gary Gygax's Artifact of Evil, a "Gord the Rogue" novel set in Greyhawk. I tried to hue as closely as possible to the description of these "ape-orcs" as possible, although certain amount of interpretation was necessary in order to shoe-horn them into AD&D stats. The following is not an original work, is merely "fan-fiction" based on a monster as described in one of Gary's novels, and I certainly make no claim to copyright on this entry.
FREQUENCY: Very rare (uncommon)
NO. APPEARING: 10-60
% IN LAIR: 20%
MOVE: 12” @ 12”
ALIGNMENT: Chaotic evil
TREASURE TYPE: Individual: K; Lair: O, P, Q (x5)
HIT DICE: 2
ARMOR CLASS: 7
NO. OF ATTACKS: 1 or 3
DAMAGE/ATTACK: By weapon type, or 1-2/1-2/1-4
SPECIAL ATTACKS: Surprise 1-3 (d6)
SPECIAL DEFENSES: Nil
SPECIAL ABILITIES: Infravision 60 feet
MAGIC RESISTANCE: Standard
PSIONIC ABILITY: Nil
ATTACK/DEFENSE MODES: Nil
Losel, or “lost ones,” are arboreal simian-orc crossbreeds, rather stupid and favoring their simian origins. They are as at home in the tree tops as they are upon the ground. They mainly inhabit the Vesve forest, where they are quite commonly found, and it is said that they are bred by Iuz or one of his minions.
They are usually armed with throwing clubs or hand axes for ranged weapons, or occasionally with light crossbows. In melee, they will fight with scimitars, axes, clubs, daggers, or short swords. They wear leather or hide armor, but they don't use shields. If unarmed, they will scratch with their weak claws, as well as bite with their fangs. Losel are adept at moving quietly and ambushing from the tree tops; whenever attacking from such a position, they surprise opponents 1-3 on a d6.
Losel run at a shambling gait, swinging their long arms much as an ape would do. They are covered in dark, matted fur, and they smell worse than true orcs if that is possible. Losel are quite cowardly, groveling and sniveling whenever they are bullied by a strong master. They speak a broken form of common that is often difficult to understand, as well as their own orcish dialect, both of which are often intermixed with simian-like chatterings and snarls. They have infravision out to a range of 60 feet. Losel crave man flesh, and will gladly accept such as payment in lieu of treasure whenever possible. Losel often hunt using bird whistles or mimicking the sounds of other animals as communication between different hunting bands.