Anyone interested in doing a time travel campaign set in Greyhawk check out Maldin's site
Chronomancy is a major influence in my current campaign, also set in the World of Greyhawk. The undersea adventure centers around three “Mysterious Places”; Turucambi, The Sinking Isle, and the Jungle of Lost Ships. The party seeks to thwart the plans of the blackwater hag Diadema, who wishes to awaken three magical maelstroms to drain the ocean.
Per prior publications, in the Jungle of Lost Ships there is a "ship made of metal, with no mast or oars...", while in Turucambi there is "a huge sunken hulk more than a hundred feet long, with many masts and a slender, shallow body (a clipper ship, such as was known on Earth in the 1800s)”. I added a submersible beneath the Sinking Isle, to complete the set.
All three were temporally displaced geocaches, clues supposedly placed by the main protagonist NPC, a spirit hag named Xaetra. Each was a “twice-named ship” with the name Enora Norray placed over the actual ship’s name (I made the metal ship in the JoLS the ironclad USS Monitor). Within each ship was a specific tome detailing the means by which Xaetra could be restored to life, from her current existence as an ethereal spirit hag.
It was foretold that Xaetra would be restored to life, take on the mantle of Chronomancer, then travel back in time to leave clues detailing the means of her resurrection; i.e. everything I know about time travel, I learned from Bill & Ted.

At some point, Xaetra would travel into the distant past, where she would lose her memory and begin life anew, transformed into the likeness of a human.
The prophesy was misinterpreted, for it was not Xaetra who would learn to swim the streams of time. It was her daughter Jaenan. In her time beneath the surface of the Dramidj Ocean, Xaetra bonded with the cold machinations of a metal construct devised by her paramour Zander, a powerful lich. Zander had used the remains of clockwork horrors, a quarut inevitable, and the mysterious metal orichalcum to craft his creation. The iron hag, amalgamation of spirit and steel, became known as grandmother clock. Together the two conceived a mechanatrix child, Jaenan, daughter of skin, steel, and sorcery.
Jaenan was not a typical child, for she aged in unpredictable spurts. Within the matter of a year, she had aged to resemble a child of twelve. Jaenan had been charged with protecting the remains of the iron hag, after it was destroyed by the abyssal hag Syliah. Jaenan had learned to incorporate bits of the construct into her own being, wearing a half-mask and single gauntlet made from Grandmother Clock.
For a time, Jaenan was on her own. Inadvertently, she had released the hydrimera, a beast who became known as the Leviathan of the Devils’ Purse. She sought to atone for her mistake. She made her way to the undersea fortress of Drawmij, which she found seemingly abandoned. There, she learned the ways of Chronomancy.
Using the gauntlet of the iron hag, she forged Xaetra’s handwriting to pen the three Tomes of Apotheosis. Using the mask of the iron hag, she watched Xaetra’s every move. Jaenan traveled back in time, to place the clues within the twice-named ships she had summoned. Yet it was the last of the vessels, lodged within the Weed-Sea, which would be her undoing.
When the USS Monitor returned to the time beyond time, Jaenan was lost. The party would never know that Jaenan would be the one to travel into the distant past, lose her memory and begin her life anew. In time, Jaenan, now known as Chrysa, would be cursed. At the hands of a marid, she was transformed into a living whirlpool and driven mad.
In her elemental form, Chrysa would have many children. These tiny elementals, known as elementites, would in time form three magical maelstroms. Only by swimming within each vortex, could the party learn their secrets to become the Masters of the Maelstrom.
Yes, I have too much fun, for people.
