Mark of Cain (Omniverse)

The Mark of Cain is the source of power for the weapon, The First Blade, in the series Power Rangers: Omniverse

History
The Mark of Cain or also known as "The Mark of the Beast" is the source of The First Blade's power. It is one half of the weapon that Cain used against the rest of the Knights of Hell. Cain later transferred the Mark to Kurt, so he could kill the last Knight of Hell, Abaddon.

When Kurt used the First Blade for the first time, he felt a murderous rage that did not dissipate after he killed a victim with it. It later gave him immunity to Abaddon's powers and telekinesis and have a telekinetic control of the blade, all with great concentration, allowing him to overcome and kill her. After killing Abaddon, this rage caused him to mutilate her corpse. He also displayed superhuman strength while fighting a vampire. Kurt later showed precognition, receiving a nightmare about a slaughter he would later commit under the Mark's influence. When a human with the Mark refuses to give into its rage, it seems to keep them from being able to access its other abilities as when Kurt fought Cain and didn't give into the Mark's rage, he displayed no extraordinary abilities which Cain noted. However, though mostly due to the devil's trap Cain was confined in that bound most of his powers, Kurt proved capable of defeating Cain even without the Mark's abilities while Cain with the Mark's abilities couldn't defeat him.

When the bearer of the Mark receives a mortal wound that would kill them, the Mark converts their soul into a demon, also becoming the likes of the Knight of Hell, so that it can live on, and cause further chaos amongst others. It is also revealed that if the bearer does not satisfy the mark, by killing, it will slowly but steadily turn them into a demon (presumably to make them willing to kill). Castiel explains that the grip of the mark affects the bearer on more than just a purely physical level, and that cutting it off or even burning it off wouldn't work and it would require a source of great power. He even stated that it reaches back to the time of creation itself and that it predates the lore. According to Metatron, there is a way to remove it and it requires the First Blade to work. Conversely, Cain himself claims there is no cure. Metatron later admitted about lying about knowing how to remove the Mark though Rita claimed it is simply a curse, the oldest curse in existence but even she doesn't know how to remove it