The Erda were a Vulcan Elf tribe native to the namesake Erda Islands, a volcanic island chain straddling the border between the Leir Sea and Heznland during Erudite's Tribal Age. The Erda worshiped the god Ardas, who largely forbade them from leaving their island home.
Eventually, the Erda went to war with the Wasari, and took the Worldstone, a relic of great power, for themselves. With the power of the Worldstone, the Erda were able to make the Erda Isles much safer for their people, but they enraged the Wasari god, Wasa. The resulting conflict between Ardas and Wasa permanently reduced Leir to a desert.
Following the war between the gods, the remnants of the Erda Tribe left behind their homes, now charred and surrounded by desert, and migrated inland to Heznland.