The Mysterious Adventurer is a player spoof member of the Myths' Guild. He is located north-west on the guild's ground floor[UK]1st floor[US].
He wears a Black d'hide body, chaps, Dragon boots, Barrows gloves, Helm of neitiznot, amulet of fury and a Mythical cape, and wields a Zamorakian spear.
- The Mysterious Adventurer is a reference to the player named Woox, who gained popularity by being the first to defeat the Corporeal Beast solo in 2009. The equipment the Mysterious Adventurer wears, excluding the mythical cape, is the same equipment Woox used when he first defeated the Corporeal Beast solo.
- The Mysterious Adventurer is also a possible reference to Red from the Pokemon series, found at the end of Pokémon Gold and Silver. Red represents the player character of the previous Pokémon game, who in the time between games has become a master Pokémon trainer and accomplished everything. The Adventurer's dialogue is also the same as Red's.