The greater Werewolves were Maia-Spirits of great power while the lesser Werewolves - or true Wargs - were but mighty undead beasts.
These creatures could alter their form so that they were able to stand upright and use their clawlike hands, but they couldn't transform themselves into Men. While Werewolves possessed the intelligence of the Secondborn — and though they would speak, use tools, and cast spells — they remained Wolf-like in their nature. Only a few maiarin Werewolves still possessed the ability to change their form into a more human-like appearance.
In MERP, the Term Werewolf is also sometimes applied to mannish-werewolves, shapeshifters or beastmen, created by Dark Magical experiments.One source of these mannish werewolves was he Shapeshifter-disease, a magical plight created by the Necromancer of Dol Guldur.The Scara-Hai were an orcish tribe and breed of Mordor-Orcs who had the werewolf-like ability to transform into great wolves.