- Reward from the Royal Sorcerer Navlaan after showing him the Sunset Staff when asked to assassinate Felkin the Outcast.
Forbidden Sun is a powerful projectile spell reminiscent of the Demon's Souls variant of Fireball. Casting it releases a large ball of fire that quickly travels towards the target in a slightly arced trajectory; upon reaching the target, the fireball explodes, dealing damage and leaving behind a short-lived pool of lava. The spell benefits from moderately high damage, as well as very fast casting time; this is offset by its low number of casts and its very high slot requirement.
While the damage of this spell is outdone by Great Chaos Fireball and Flame Swathe, its true strength lies in its surprisingly low casting time and alarming travel speed. This serves as one of the more useful spells overall in PvP as it can be used to take near instant advantage of openings in the enemy's defenses.
Like all other spells, the amount of casts per slot increases upon reaching certain Attunement milestones:
|Attunement Level||Amount of Casts|
| Acid Surge • Chaos Storm • Combustion • Dance of Fire • Fire Orb • Fire Tempest • Fire Whip • Fireball|
Fire Snake • Firestorm • Flame Swathe • Flame Weapon • Flash Sweat • Forbidden Sun • Great Chaos Fireball
Great Combustion • Great Fireball • Immolation • Iron Flesh • Lingering Flame • Outcry • Poison Mist • Toxic Mist • Warmth