Abaddon was one of only two remaining Knights of Hell, the other being her retired master, Cain. Abaddon was single-handedly responsible for the extinction of the original Men of Letters. She arrived in the present through time travel in her hunt for Henry Winchester and the key of the Order of Letters he was entrusted with but failed to retrieve it, with Henry's grandsons Sam and Dean Winchester taking it instead. Upon discovering the shameful state Hell had fallen into in her absence, however, Abaddon abandoned her hunt for the key and began a crusade to take over Hell herself to remake the world as she saw fit—with herself as Queen of Hell, ruling over demons, angels, and humans alike. As part of her plan she had her few loyal demons pull the souls from innocent people to bring these souls to Hell to turn into demons. In an attempt to use Crowley to trap the Winchesters, Abaddon was killed by Dean with The First Blade after he proved immune to her powers due to the Mark of Cain.
Powers and Stats
Name: Abaddon, The Queen
Classification: Knight of Hell, Demon, Human (Formerly)
Powers and Abilities: Superhuman Physical Characteristics, Immortality (Types 1 and 3), Regeneration (Mid-Low), Teleportation, Time Travel Spells, Telekinesis, Exorcism, Memory Extraction, Magic User, Teleportation, Telepathy, Flight, Terrakinesis, Biokinesis, Electrokinesis, Weather Manipulation, Immunity to most Demon-Killing spells and weapons
Lifting Strength: Class 5
Striking Strength: Town Class
Durability: Town level (Although the nature of her true form makes her difficult to kill)
Range: Melee for Combat, Small Building level for Most abilities, Several Kilometers with Weather Manipulation. Likely Planetary with Teleportation
Intelligence: Quite High. Thousands of Years of experience. Knowledgeable in Magic and Secret Society, and a military genius.
Weaknesses: Holy Water, Devil's Trap, Higher Beings, The First Blade