Erathia is a kingdom on the continent of Antagarich in Enroth. It is ruled by Gryphonheart dynasty, and it is inhabited mostly by the humans of the Castle town. Its capital city is Steadwick. Most of the campaigns in Heroes of Might and Magic III - 埃拉西亚的光复 and its expansions 末日之刃 and 死亡阴影 take place in Erathia.
The nation was founded by Rion Gryphonheart during his uprising against the Barbarian King Tarnum. The throne remained in the hands of the Gryphonheart dynasty until Queen Catherine married Roland Ironfist of Enroth. Queen Catherine Ironfist (Gryphonheart) stepped down as the Queen of Erathia during the final events of Armageddon's Blade, and she no longer had authority to command her father's kingdom. The throne fell to Gen. Morgan Kendal, the highest General in Erathia and the commander of the Royal Erathian Military Command, who had previously ruled the kingdom after the murder of King Nicolas Gryphonheart. General Kendal was the last ruler of the kingdom of Erathia.