Quote1 The scum of the earth called me Eclipso. But here... I was Lord Kalaa. Lord of the Black Diamond. Quote2
-- Lord Kalaa of House Onyx src

Once Lord of House Onyx, he was banished from Nilaa to Prime Earth by Lady Chandra, and imprisoned in the Black Diamond.

Long ago, in the world of Nilaa, the Lord of House Onyx formed a blood pairing with the Lady of House Diamond. The result of their union was a child named Kalaa. The dormant powers of both houses twisted his evil soul. When he became a man, he killed his parents, and received both of their blood-power by means of a Black Diamond. By virtue of his both having been born on an eclipse and gaining his powers during one, Kalaa was tied to the darkness of a total solar eclipse.[1]

During the eclipse, his power was magnified tenfold, and his evil was so great that the other Houses banded together against him in the War of the Eclipse. Thanks to the fact that he could not enslave those who bore the blood-power of their Houses, Lady Chandra of House Amethyst was able to defeat him by opening a portal and dragging him to First Home, where he was trapped in the Black Diamond for centuries.[2]

Lady Chandra had hoped to destroy him there, but she clearly failed, and the black diamond survived with the essence of Lord Kalaa inside it until he could find a physical host.[3]

The diamond ended up in Hell. In the early 11th century AD, it was taken to Earth by the Amazon Exoristos, who found that she grew more violent with it in her possession.[4]. She left it with Al Jabr in the Moorish city of Al-Wadi, where by 1043 Lord Kalaa's influence had turned a once proud city into a place of crime and corruption[5]. Following the discovery of the Holy Grail by the Demon Knights in a giants' stronghold it was used to balance the effects of the diamond.[6]

Eventually, the stone was discovered by Dr. Henry Jekyll, who used it to create the formula that would transform him into Mister Hyde, a monster consumed by the rage and power of Lord Kalaa.[7]

Nearly a century later, the Diamond had been housed on Sentinel Island, where it was protected by the ghosts of all of those who died there. It was discovered there by Team 7, who, in an effort to counter a plan by Basilisk to use the Black Diamond's power against metahumans, retrieved it. In the process, Slade Wilson became possessed by the spirit in the Diamond. After he was freed, the stone was hidden away in the Black Room.[8]

Five years later, Catwoman was contracted to infiltrate the Black Room and steal the Black Diamond, nearly becoming possessed herself. After retrieving it safely, it was delivered to Alex Montez, who became completely possessed by Eclipso.[9]

John Constantine, who had stolen a portal crystal to Nilaa when Princess Amaya returned there[10], knew that Eclipso posed a threat to the earth, and decided to use the favour Amaya owed him (in exchange for having bought her pizza) to get Eclipso back to Nilaa, and off of Earth. Upon his return to Nilaa, Eclipso introduced himself as Lord Kalaa, and murdered Lady Senshe of House Citrine before beginning his quest to regain control of Nilaa[11].

His first move was to return to House Onyx to take control of his people there, though he failed to kill the current House's Lady Akikra. Taking her people with him, he then went to House Diamond, where he offered Lord Reishan the opportunity to surrender freely to him. The Lord refused, and was immediately beheaded, causing the blood power of his House to transfer into his son Zushan. Wilier than his father and brother, Zushan surrendered, and turned on his own brother Hadran, who was saved at the last by Lady Akikra.

With the combined Houses of Onyx and Diamond under his command, Kalaa lead his attack against House Amethyst, requiring that the disparate factions within that House unite against him.[12]