Demon Overlord Seedle is the Overlord of the Underworld (making him the "Underlord"). Though he was once an honorable samurai said to be a part of a party of 'Braves' the circumstances of his death left him filled with an unnatural fury that allowed him to force his way into becoming Overlord.
While he was still alive he had become obsessed with a still alive Salome. One night during their journey he forced himself on Salome but she stabbed him to death and fled. Because of this Seedle holds an intense hatred for Salome as being killed by a woman wounded his ego. He was later killed by Alex.
Source: Wikipedia, "Makai Kingdom: Chronicles of the Sacred Tome," available under the CC-BY-SA License.