WARNING: The following article contains major spoilers for Justice League Dark #16 by James Tynion IV, Alvero Martinez Bueno, Fernando Blanco, Raul Fernandez, Rob Leigh and Brad Anderson, on sale now.
Justice League Dark has been reshaping the very concept of magic in the DC Universe for quite some time. Hecate was revealed as the avatar for the ethereal power, with magic being merely an extension of the pure light that led to creation. Now, with Circe backstabbing Wonder Woman and company after repelling the Otherkind, she's wielding the power of Hecate and manipulating the heroes for some sinister purpose.
Issue #16 reveals exactly what Circe needs to complete the job, and it turns out to be the Heart of Darkness storing the demonic Eclipso. However, as we find out why she needs the villain, the creative team retcons Eclipso's origin story once more.
Eclipso started as a more limited villain, empowered only during eclipses by the Wrath of God, and was replaced by the Spectre in the '90s. He was basically God's revenge, even causing Noah's flood. Come the New 52, another retcon shaped him as the God of Vengeance, who initially came from Gemworld and possessed people to wreak havoc. It got even worse in the DC Rebirth era when he possessed Max Lord during the Justice League vs. Suicide Squad event, but luckily Diana trapped him in his diamond once more, weakened and without an avatar.
Now, in her secret vault underneath the Hall of Justice, with Kent Nelson (the former Doctor Fate) and Zatanna shocked at all the magical relics Wonder Woman's collected and hidden away, it's revealed she's been holding Eclipso there as a prisoner. However, when the magicians use his moon connection to send Diana to the Collective Unconscious/Circe's secret realm, we learn of Eclipso' true nature, complete with an adjusted backstory.
When Hecate came to life, she removed the darker half of herself: the Upside Down Man. This was so she could never be corrupted, but seeing as it made her unstoppable, the other powers-that-be in the DC Universe back then created a being of dark magic to rival her. This spirit mirrored the dark version of Hecate and was formed to battle her if she ever became too powerful, and it became known as Eclipso. Basically, he was a failsafe created to eclipse Hecate, and that's why Circe has been playing Diana all along, so she could have access to his diamond prison.
This is an intriguing retcon because it means DC will at some point have to reveal who these other powers-that-be were, as it seems Tynion has shifted away from having God as Eclipso's master. It could be the first pantheon of Gods -- the Greeks and Egyptians -- but that'll have to be cleared up. But as it stands, once Circe gets the Heart of Darkness, seeing as she already possesses half of Hecate's power, she'll become the true embodiment of magic.
From future solicits, it seems Eclipso will give himself up willingly and partner with her, maybe even using Circe as a host, but once she becomes this goddess of the mystical realm, she could truly surpass anything Hecate's ever done. After all, Eclipso will surely corrupt her and push her over the edge, which means Diana will need all the heavy-hitters on deck. Constantine is off the team for now, Swamp Thing has been reduced to sludge and Kent and Zatanna are trying to protect the diamond. But with Circe tricking Diana and now possessing her to go steal the diamond, Wonder Woman clearly just played into the villain's hands and doomed the supernatural dimension in a big way. Eclipso has never been a villain to mess with, and now it seems he's more powerful than we assumed, and with Circe next to him, it truly could change things forever.
Justice League Dark #17 goes on sale Nov. 27.