Dunheely Weller (ダンヒーリー・ウェラー) was Cäcilie von Spitzweg's second husband and Conrart's father. Dunheely was a human who traveled around with only a sword, until he fell in love with Celi and settled down in Luttenberg. He became the first Lord of Luttenberg.
His father was named Glen Gorden Weller (グレン・ゴードン・ウェラー), and he's remembered as the final descendant of the three Kings of Shimaron. He was banished from Big Shimaron and they placed two tattoos on his left arm, a symbol of banishment, and after that in Shimaron they told the public that the line had come to an end.
Despite resistance, he married Cäcilie and had a son, Conrart. Celi herself admitted that their wedding was approved by Shinou. In his youth, Dunheely took Conrad on trips with him to the human lands. Dunheely championed the rights of half-human, half-Mazoku and spent decades in making their lives better. It is known later on that an ancestor of the Weller family was entrusted with the key (left arm) for one of the Forbidden boxes. Dunheely kept the family secret and became a wandering swordsman of amazing prowess.
In the anime, Dunheely wanted proof of his life. Gwendal detested him, having the pride of a Mazoku, as Dunheely stated. However, after taking Gwendal along for a trip to settle their duel, Gwendal changes his opinions of Dunheely. While appearing young to Gwendals' eyes, Dunheely was actually an old man by the time he and Gwendal fought off bandits to keep the Nameless Village safe.