The Ripper was a Zamorakian ripper demon that lived during the God Wars, where it was used by the forces of Zamorak as an assassin to kill important targets such as heroes and commanders in the Saradominist ranks. It is featured heavily in the lore The Song From Before The War, in which it is killed by Elspeth's song. It is notable in that it seems to act alone, whereas most other Ripper Demons work in packs.
The Ripper attacked a village and mortally wounded Sergeant Mazakon. However, Elspeth kept the village safe by continually singing - her song was so beautiful and holy that the demon was repelled by it. However, as the demon waited outside the village, Elspeth grew weak. Knowing that she could not continue much longer, Elspeth approached the Ripper in the hope that it would spare the village after attacking her. The Ripper attacked Elspeth but before her death Saradomin gave her the strength to sing one final, piercing note that shook to ash the demon's heart and saved the village.
However, the Ripper survived, although its corpse was mangled and was unable to do anything until Jebediah Omnis hired a group of miners to find the corpse. Jebediah performed a ritual to allow the Ripper to search for new hosts, which it consumed and turned them into Ripper demons. As of now, it bides its time inside the mine, controlling those it had possessed.
In One Piercing Note
As some demons are known to be immortal, the Ripper was thought to have returned as the Killer during the One Piercing Note quest, where an unknown attacker kills off various sisters of the Abbey of St. Elspeth Citharede. However, it is finally discovered that the killer is a sister of the abbey, and not the Ripper.