OSRS Forthos Dungeon Altar Guide for Prayer Training and Lore
Old School RuneScape (OSRS) players looking to optimize their Prayer training or dive into the rich lore of Great Kourend will find the Forthos Dungeon Altar a hidden gem. Located beneath the Forthos Ruin in Hosidius, this altar in the Altar of the Sun room offers a unique way to recharge Prayer points and engage with the dungeon’s immersive mechanics. In this guide, we’ll explore the altar’s functionality, its role in Prayer training, how to navigate its challenges, and the intriguing consequences tied to in-game choices, all while uncovering the lore of this fascinating dungeon.
The Forthos Dungeon, introduced in 2019 as part of the Hosidius Rework, is an underground temple filled with spiders, dragons, and undead creatures. Its design draws inspiration from classic dungeons like Taverley, emphasizing exploration and self-sustainability for players, especially Ironmen. The Altar of the Sun, located near the temple library, is a key feature, allowing players to recharge their Prayer points, making it a hotspot for training against nearby undead druids.
Location and Access
The Altar of the Sun is situated in the Altar of the Sun room, close to the temple library containing level-105 undead druids. To reach the dungeon, players can use:
- Xeric’s Talisman: Teleport to Xeric’s Glade, just east of the eastern entrance.
- Skills Necklace: Teleport to the Woodcutting Guild, west of the western entrance.
- Kourend Castle Teleport: Access either entrance from the castle courtyard.
- Combat Bracelet: Teleport to the Ranging Guild for a quick route to the entrances.
No specific quest or level requirements are needed to enter the dungeon, making it accessible to mid-level players (recommended combat level 100+). The altar’s proximity to enemies like undead druids makes it ideal for sustained combat training with Prayer.
Altar Functionality
The altar restores a player’s Prayer points to full when used, similar to other altars in Gielinor. Its strategic location allows players to maintain protection prayers while fighting nearby monsters, reducing the need for Prayer potions. However, the altar can become cursed, rendering it unusable under specific conditions, which we’ll explore later.
Prayer Training with the Forthos Dungeon Altar
The altar’s synergy with the dungeon’s monsters and the nearby Sacred Bone Burner makes it a compelling choice for Prayer training, particularly for Ironmen or players seeking alternatives to the Gilded Altar or Chaos Altar.
Using the Sacred Bone Burner
In the Sacrificial Chamber, accessible via the Crypt of the Moon, players can use the Sacred Bone Burner to sacrifice bones for three times the base Prayer experience of burying them. This is less efficient than the Ectofuntus (4x) or Gilded Altar (3.5x) but offers a unique advantage due to the dungeon’s self-sustaining drops, like dragon bones from red dragons.
| Bone Type | Base Bury XP | Bone Burner XP (3x) |
|---|---|---|
| Regular Bones | 4.5 | 13.5 |
| Baby Dragon Bones | 30 | 90 |
| Dragon Bones | 72 | 216 |
Burning enough bones grants the Temple Key, which permanently unlocks doors in the dungeon, easing navigation. This makes the altar and bone burner a practical choice for players slaying red dragons or baby red dragons in the dungeon.
Training Against Undead Druids
The temple library, just north of the altar, houses four level-105 undead druids. These enemies are ideal for mid-level players training combat with Prayer, as the altar allows continuous use of protection prayers. Recommended gear includes:
- Armour: Barrows or better for balanced melee and magic defense.
- Weapon: Abyssal Whip or better for efficient damage.
- Inventory: Food (e.g., sharks), Grubby Key for chest access, and teleportation items.
The undead druids drop tattered tome pages, which can be turned in at the Arceuus Library for 1,000 coins each after completing the “In Search of Knowledge” miniquest, adding a small gold-making incentive.
The Olbertus Dilemma and Altar Consequences
One of the most intriguing aspects of the Altar of the Sun is its interaction with the NPC Olbertus, who stands nearby with a curious artifact. Player choices involving Olbertus can drastically affect the altar’s usability, emphasizing the dungeon’s theme of consequence.
Interacting with Olbertus
Players can either trade Olbertus five unnoted cut dragonstones for a temple coin or attempt to kill him. Choosing to attack triggers a transformation into a level-186 Shaeded Beast, a formidable foe. Defeating or fleeing from the beast results in the altar becoming cursed, rendering it unusable and causing up to 30 damage plus full Prayer depletion if interacted with.
Un-Cursing the Altar
To restore the altar, players must offer 200 eligible dragon bones (baby dragon or dragon bones) to the Sacred Bone Burner. This process originally granted Prayer XP, posing a challenge for “pure” accounts avoiding Prayer experience. However, a 2019 update ensured no XP is gained while the altar is cursed, making it safe for pures to un-curse it.
Note: Once the altar is cursed, the decision is permanent for that account, reinforcing the dungeon’s RPG-like choice mechanics. Players who avoid killing Olbertus retain full altar functionality without complications.
Lore and Miniquest Connections
The Forthos Dungeon is steeped in lore about an ancient druidic religion, with the Altar of the Sun playing a central role. The dungeon’s rooms, including the Sacrificial Chamber and temple library, hint at a forgotten conflict between opposing religious factions, now overrun by undead creatures and Sarachnis, the spider boss.
In Search of Knowledge Miniquest
The “In Search of Knowledge” miniquest ties directly to the altar’s lore. Players heal Brother Aimeri in the Spider’s Den, who provides information about tattered tomes in the temple library. Collecting four pages per tome (dropped by dungeon creatures) and turning in all three tomes to the Arceuus Library rewards a 10,000 XP lamp. The tomes reveal snippets about the druidic religion and the dungeon’s history, enhancing the narrative experience.
Altar of the Sun and Sun Spear
The altar is also used to recharge the Sun Spear, an ancient weapon linked to the legendary hero Robert the Strong. Players with a charged Sun Spear can interact with the altar to restore Prayer points, though this is a niche mechanic tied to specific lore interactions.
Tips for Maximizing the Forthos Dungeon Altar
To make the most of the Altar of the Sun, consider these practical tips:
- Avoid Killing Olbertus: Unless you’re prepared to face the Shaeded Beast and curse the altar, trade dragonstones instead to keep the altar functional.
- Farm Red Dragons: The dungeon’s six red dragons and five baby red dragons drop bones ideal for the bone burner, supporting both Prayer training and Temple Key acquisition.
- Complete the Miniquest: The “In Search of Knowledge” miniquest is straightforward and unlocks additional rewards from tome pages, boosting gold income.
- Use the Grubby Chest: Accessible with a Grubby Key (dropped by dungeon creatures) and 57 Thieving, the chest provides supplies to sustain longer trips.
- Leverage Eodan’s Tanning Stall: Located in the Sacrificial Chamber, Eodan’s stall allows tanning dragonhides, with reduced prices after completing Kourend & Kebos Achievement Diary tiers.
For Ironmen, the dungeon’s self-contained design, with the altar, bone burner, and Grubby Chest, makes it an excellent spot for prolonged training sessions without reliance on external resources.
The Forthos Dungeon Altar is more than just a Prayer recharge point—it’s a gateway to efficient training, engaging lore, and meaningful player choices. Whether you’re battling undead druids, uncovering the dungeon’s history, or carefully navigating Olbertus’s consequences, the Altar of the Sun offers a rewarding experience for OSRS adventurers. Gear up, explore the dungeon, and make your choices wisely to unlock the full potential of this underrated feature.