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.