Euhorn Jacob Kaldwin I was the former Emperor of the the Isles, the first of the Kaldwin Dynasty to rule, father to Delilah Copperspoon and Empress Jessamine Kaldwin, and grandfather of Empress Emily Kaldwin.
In 1803, Euhorn was crowned Emperor after the previous royal dynasty provided no heirs, despite the Kaldwin family's "distance to the throne". His rule was met with an age of prosperity, as the construction of Kaldwin's Bridge began and the Dunwall Sewers were reinforced and expanded to stop repeated collapse.
He first fathered Delilah, his illegitimate daughter mothered by a Dunwall Tower kitchen maid. Approximately a year later, he went on to father Jessamine with his wife Beatrix, who died during the unsuccessful birth of their second child. He also knew Corvo Attano, who was gifted to him by Duke Theodanis Abele and would later serve as Jessamine's Lord Protector.
- According to the Heart, Euhorn had golden hair even though Delilah's painting seems to indicate it is dark.
- Under Euhorn's reign, Dunwall Tower grounds were made open to the public during the day.