Auberon Muircetach, also known as "King of the Alders", was the king of the Aen Elle, an Aen Saevherne and ruler of Tir ná Lia. According to Avallac'h he was at least 650 saovines old. Though a mature elf with grey long hair, he maintained a slender and boyish figure.
He was determined to reclaim the Elder Blood that had been "stolen" from the Aen Elle by Cregennan when he took Lara Dorren as his lover. To achieve this, he ordered Ciri, a descendent of Lara, brought to him and groomed to produce his heir. After Avallac'h had brought him Ciri, he took her to bed where many times but without completing the act. This made Ciri doubt he wanted to conceive a child with her, which angered her greatly, because Avallac'h had promised her freedom once she had delivered Auberon an heir. Before he and Ciri were able to conceive, he was unwittingly killed from an overdose of an aphrodisiac supplied by Eredin Bréacc Glas.
The Witcher 3: Wild Hunt In 1272, Geralt and Avallac'h travel to the world of the Aen Elle to meet with Ge'els, Eredin's viceroy and administrator, to convince him of Eredin's regicide of Auberon so he could deny Eredin reinforcement when they lure him out. They bring Ge'els to Novigrad to be shown the proof through an oneiromancer named Corinne Tilly, as she could show visions that can't be fabricated. Once Ge'els experiences the vision, he is convinced and tells Geralt and his companions to seek the Sunstone on Skellige to lure Eredin out.
Note
In medieval and renaissance literature, Oberon (or Auberon), is the king of fairies. He is a prominent character in A Midsummer Night Dream by William Shakespeare.
Another reference to classical literature may be Auberon's sobriquet "King of the Alders" which is a literal translation of Erlkönig - a mythical king of the fairies from the German and Scandinavian folklore. He is the main protagonist of Johann Wolfgang von Goethe's 1782 poem of the same name.
Though he was a wise Aen Saevherne, he used the drug fisstech.