Zankou's History
Zankou was an ancient and extremely powerful upper-level demon who was feared, even by his own kind. Intelligent and ruthless, his understanding of the human nature made him able to manipulate and prey on the weaknesses of his enemies.
His greatest feats include the Crusades, the September Massacres, and the Black Plague. His abilities and ambition became so great that he eventually contested the Source of All Evil for control over the Underworld. However, the Source was able to imprison Zankou within a magical barrier deep within the Underworld.
Zankou formed one of the biggest threats ever to the Charmed Ones, but his reign of terror came to an end in 2005 with the destruction of the Nexus beneath the Halliwell Manor, which took him along with it.
Freed from Imprisonment:
Zankou was released from his prison by a group of demons who believed he was the only one who could prevent the impending attack of the Avatars. Although several demons were opposed to his release, he was eventually released because he was their only hope. Reluctantly, several demons went to his prison and freed him. Zankou then revealed he was aware of everything that had happened in the world and proceeded to absorb the powers of a Shapeshifter. He then used this power to get close the Seer Kyra, who was planning on betraying the demons, and vanquished her for her betrayal.
Fight against the Avatars:
Originally, Zankou helped the Charmed Ones in their fight with the Avatars along with Leo Wyatt and Kyle Brody, realizing that their Utopia threatened all of demonic existence. The sisters teamed up with Zankou after they realized the cost utopia was free will itself. They confronted the Avatars at their headquarters and forced them to revert Utopia.
Attempt to control the Nexus:
After the Avatars retreated, Zankou set his sights on obtaining the Nexus. The first time was in "Scry Hard", when he tried to get the sisters to cast a spell so that he could get the Nexus, but his attempt failed because the Nexus could not choose between the Power of Three and Zankou. Instead, it went to Leo. The second attempt was in "Something Wicca This Way Goes...?", when he took over the Halliwell Manor, while the Charmed Ones were at Magic School, and took in the Nexus. However, the Charmed Ones were spying and used a spell to draw it out of him.
Stealing the Book of Shadows:
Zankou began to mobilize the Underworld in hopes to control it. He attempted to steal the Book of Shadows on various occasions. He even hired a demonic alchemist to brainwash resurrected zombie innocents that the Charmed Ones were previously unable to save into attacking them.
Stealing Piper and Phoebe's Powers:
After breaking through the protective barrier that the Book of Shadows wields due to weakening the sister's bond as well as their confidence in themselves and in their magic, Zankou retrieved the Book and created the potion in a diabolical plan to steal the Charmed Ones' powers. He then attacked the sisters in the Attic and distracted the girls by firing an energy ball at Piper Halliwell, who Paige and Phoebe then tended to. With their backs turned towards Zankou, he threw the potion at Phoebe and absorbed her power of Premonition. After the acquisition of this power, he was able to foresee the sisters going to seek help from the Vampire Queen and he got to her first.
The sisters went to the Queen for assistance and she feigned being on the girls' side. Thinking the Queen was on their side, they then orbed to the Manor where Zankou was waiting for them; he told them he got to the Queen first. He attacked and threw the potion at Piper and absorbed her powers of Molecular Immobilization and Combustion. Zankou then used the Combustion power on Piper sending her flying backwards. With Piper and Phoebe's powers, he gained enough access to the Book's magic, and found a way to break through Magic School's defenses, where he planned to take Paige's powers. He threw the potion at her but it did not work, because she was in astral mode at the time. The three then disappeared, leaving him shocked and confused.
The Charmed Ones destroy Zankou:
The Charmed Ones returned to their bodies and used what little time they had to take back the Book of Shadows. Zankou then confronted them at the Manor, where the sisters tricked him into absorbing the Nexus into his body and then cast the spell designed specifically to destroy it, thus destroying Zankou in the process.
Resurrection through Tyler Michaels:
Five years after his vanquish, Zankou returned through Tyler Michaels, who came in contact with Heremus's blood and became a vessel for vanquished demons to return. Zankou attacked Benjamin Turner and Kyra, then attempted to attack the Charmed Ones to gain the power of the All. Prue then inserted her magic into him, overloading his body until he exploded, revealing a living Tyler.