Horace Highwater is a friend of Sidney Ruffleberg, the creator of Antiqua, and one of the four leaders of Evermore. Unlike the other leaders of Evermore, Horace (at first) does not actively lead Antiqua, instead just heading an archaeological dig site near the ruins of the region.
30 years ago, Horace was involved in the original experiment that created Evermore. Horace was the curator of the Podunk Museum of Natural History, and a specialist in early civilizations, and so Antiqua was formed as a region that blended multiple ancient cultures together. When the experiment was sabotaged, Horace was stranded in Antiqua, and lived at his archaeological camp there.
When the Hero came to the area seeking the Diamond Eyes, they ran across Horace at his camp. Horace recognized the hero was not from Nobilia or Crustacia, and surmised he was from Podunk, believing it only a matter of time before someone else crossed over. The hero explained his quest was given to him by the ruler of Nobilia, and Horace explained he did not trust the new ruler and that he was hungry for power. The hero agreed to bring the Diamond Eyes to Horace for safekeeping, to keep any other men hired by the ruler from finding them first.
After the destruction of Aegis, Horace came to Nobilia to take command of the city now that the previous ruler was gone.
When the hero returned to Antiqua using the Windwalker, he met with Horace to retrieve the Diamond Eyes for Tinker. Horace revealed the Diamond Eyes had been taken by Tiny, who had set himself up as leader of the Oglins in the Great Pyramid. Horace gave the hero the Barrier formula to aid in confronting Tiny.
During the ending, Horace flees Evermore with the hero, leaving Nobilia in the hands of Madronius. He returns to Podunk with the other leaders, and is last seen at Professor Ruffleberg's Mansion, contemplating how they will adapt to the modern world.
When summoned using a Call Bead, Horace is able to cast Confound, First Aid, and Time Warp. His abilities are far more supportive than those of Elizabeth or Camellia. The player is also able to find the Aura and Regenerate formulas for him.