The Demonic Ruins are the remains of a copy of the fortress of Annakarl, located deep in the Wilderness. The Ruins are inhabited by greater demons and Kal'gerion demons. Inside the ruins are several burnt bone spawns, and in members' worlds, a blood rune spawn can be found nearby. The fastest way to get here is to use the Annakarl Teleport from the Ancient Magicks spellbook.
Annakarl was presumably destroyed during the battle for the Zarosian fortresses in 3100 of the Third Age during the God Wars. Prior to the introduction of the Wilderness Volcano (after being overrun with monsters) and Forinthry Dungeon, the ruins were the only place where free players could fight greater demons.
- The Demonic Ruins can be found in the Free-for-all arena of Clan Wars. However, there is no sign of the demons except for a large skeleton.
- During the RuneScape 2 beta, there was a blood rune spawn in the ruins which was accessible to both members and non-members.
- Prior to the Runescape HD update, there were two oreless rocks with a "mine" option in the ruins.
- Before the Bounty Hunter and Clan Wars updates, these ruins used to be frequented for clan wars as they are a deep wilderness multicombat zone.