The Soul obelisk located inside the Sophanem Slayer Dungeon can be interacted with to summon The Magister. Upon summoning the Magister, a Key to the Crossing will be consumed.
The Magister activates the soul obelisk when he reaches 150,000 life points. The soul obelisk will continually chip away at the player's soul, adding three Constitution debuff stacks onto the player. Each stack removes 100 life points (essentially one Constitution level). This can affect the amount of health that food can heal (i.e rocktails; others like saradomin brews are not affected).
The player can regain these stacks by doing one of the following:
- Attack the obelisk. Every 1,000 damage on the obelisk restores the player's health by 100 and removes one stack.
- Drink super restore potions. Each dose removes seven stacks from the player, but do not restore any health.