Lords of Order and Chaos have attempted to usurp control of the entire Multiverse since it first dawned untold eons ago. Perhaps the most prominent, and definitely most well known of those representing Order was Doctor Fate of Earth-Two. And his principal adversary was that of Wotan, a mysterious master of mayhem who employed powers comparable to his own as well as various other devices.
Whether he, like Fate's progenitor Nabu, originated on the planet of Celia, Wotan nevertheless was a challenge to any and all of those who would hail from there. And in a parallel universe, another echoed his eerie evil. Another entity that also had blue-green skinned, vast powers, unbridled lust for conquest, and a scheming strategist mind perhaps unmatched in the ranks of villany. Another dimensional traveling warlord arrayed in colorful plumage employing minions and machinations to meld the minds of men. Meet Dark Opal.
Dark Opal was the Lord of the House of Opal, one of the twelve kingdoms on Gemworld, itself another version of Celia. And there, he was challenged by Princess Amethyst, who herself had the genetic predisposition as a Lord of Order... since her father was one of them. As Amy Winston, she had been shielded from Opal and other opponents of order, growing up on adjacent Earth-One. Amy's Earth-Two doppleganger, Peachy Pet Thunder, never had occasion to meet Wotan although her longtime friend Inza Nelson continued to encounter this vile villain alongside boyfriend Doctor Fate. Amy was swept up in this cosmic conflict almost immediately. While on Gemworld Amy manifested her superhuman abilities, on her adopted world she was a normal girl, just as Peachy had access to similar capabilities through her step-father's Thunderbolt which ultimately led her to meeting that being's son Shocko whom she's marry and follow into the Thunderbolt Dimension. Decades previous, however, Pet wore a fabric version of the Shocko's skin and joined alongside several other girlfriends of the Justice Society when the evil Brain Wave kidnapped them. Turns out, the ladies were the ones saved when the gents came to Sharktooth Bay's tower and saved them.
So what of the histories of Opal and Wotan? For Opal, his first recorded encounters were in the pocket dimension of Gemworld wherein he attempted to consolidate the power of all the kingdoms under his headship. To that end, he used several stratagems that caused his fellow sovereigns considerable grief, until Amethyst returned to take over rulership of her house. After a series of confrontations, Opal was seemingly destroyed when his own step-son betrayed him. For Wotan, he first appeared in modern time attempting to kidnap Inza, thereby involving the Doctor in his life as the pair on three separate occasions dueled. Ultimately joining forces with other sinister cronies such as Ian Karkull, Per Degaton, even Adolph Hitler himself, Wotan was banished into another dimension seemingly for eternity.
And while Dark Opal only faced one superhero from Earth-One other than Amethyst, that being Superman...such was not the case with Opal. Since the other Lords of Gemworld had counterparts in the Lords of Order that were scattered throughout Earth-Two's universe, Wotan instead faced Fate's allies on the Justice Society including Green Lantern. On this one occasion, he dealt the caped crusader, who himself employed a powerful gem much like the Princess, a defeating blow as Lantern failed to protect a young lad whom Wotan was sent by Karkull to deal with. This boy could've been the doppleganger of Opal's own son Carnelian who ultimately was the source of his sire's greatest defeat.
Others would also utilize similar abilities, such as Doctor Zodiac of Earth-One and Lando of Earth-Two... the former a recurring foe of the Superman and Batman while the latter a heroic figure... both in World's Finest Comics! Also, Mysto aka Rick Carter and Tor aka Jim Slade who likewise had twin careers on Earths One and Two, respectively.