3,500,000 - 6,000,000 gp.
This is the third best leg armor by weight and armorpower, and the second best by armorpower. Before Update 8.2 these were unobtainable, however, after 8.2 these became a reward for a new quest, potentially making the value and rarity drop. However, after a revision to the quest, no player has been able to acquire this much sought after piece of armor.
This quest had a lot of controversy, because many felt that making the Demon Legs a quest reward would destroy a piece of Tibia history. Since they are heavier than Golden legs they are now more commonly used as a house decoration.
Obtainable in The Demon Oak Quest.