The Killing Curse was invented by Merlin the Great in the fifth year of the First Age. Orginially, no one knew of its existence and remained to killing people by other means, such as sword duels or familiar-ordered fates. The humans first came to know the spell in the fifteenth year and thus resulting in thousands of innocent deaths. Guthix was soon alerted of the spell's presence and banned the spell from ever being used again, incarcerating Merlin in the Temple of Ikov. Upon entering the prison, Merlin was stripped of all his magical abilities.
From then until the day before the Fifth Age started, Merlin was imprisoned, only until he was broken out of his cell by king of Camelot, King Arthur. King Arthur invited Merlin to stay in his castle, and Merlin agreed. However, Merlin did not stay for long, and eventually he left the castle to live a life on his own, not to be seen or heard of for another twenty years.
From then hitherto, there were many unexplained deaths. Even Guthix, being one of the only ones still around that knew of the events in the First Age, could not explain it, though the almighty diety suspected it was indeed Merlin the Great.
During the Fifth Age, the Killing Curse was strictly forbidden, only being reinstated after the death of Armillis Knight. Prior to the death of Knight, the Killing Curse was taught in school and had students try and cast it for themselves. On Knight's son's first day of his eighth year in 159, one of the wands that were used by students who forgot to buy one for themselves was presumably bewitched. When Aidan, Knight's son, attempted to cast the Killing Curse on a dummy, he was thrust around and inadvertantly killed his father. The day after, King Roald II, the then-king of Misthalin, banned the curse and it was once again illegal. After which, it was more formally banned by the king of kings, King Simivance, and then eventually officially forbidden by Guthix.
It is used almost exclusively but Zamorak, who shows no worry or hesitation when doing so. However, the Killing Curse is not the only way Zamorak kills his victims; he often resorts to beating them to death with his staff when he is most enraged, but often finishes them off with this curse, growing annoyed with his failed attempts at physical murder.
There has been controversy over the name of this spell, the Killing Curse. Some may claim that it is an obvious rip-off from the Harry Potter series, however, when confronted about the matter, the author states, "It's a curse that kills, if I were to call it a 'Killing Spell', it would make it seem as though I were trying to cover up what I was doing (not saying that I am copying J.K.'s work). But what else am I to call it?"
An actual unidentified killing curse has been shown in the game: In the quest Nomad's Requiem, Nomad kills the mage with an unidentified spell, that automatically kills him; it is shown with a bolt of green light. Of course, any spell can potentially kill your opponent with a high enough Magic level and high-leveled armour; it only matters how many lifepoints you drain from your enemy.
- Thousands of beings during the First Age
- Zamorak's father
- Zamorak (attempted)
- Zaros (attempted)
- Armillis Knight
- Unidentified Zamorakian in While Guthix Sleeps
- Many drunken men in the Blue Moon Inn
- Aidan Knight (attempted)
- Roald Remanis III (attempted)
- Shopkeeper of the Woods of Holly General Store
- Unidentified Varrock guard
- Unidentified Zamorakian in Aidan Knight: The Edicts of Guthix
- Cook in Lumbridge Castle
- Unidentified man who reported news to Zamorak
- Unidentified woman who reported news to Zamorak
- Numerous Zamorakians
- While Guthix Sleeps (First appearance)
- Aidan Knight: The Edicts of Guthix
- Aidan Knight: The Rise of Zamorak (Unconfirmed title) (Subject to return)