Lanfear (LAN-feer) (originally known as Mierin Eronaile) is one of the primary antagonists of the Wheel of Time fantasy series by Robert Jordan. She is one of the Forsaken.
Mierin Eronaile was a researcher in Collam Daan, V'saine; however she wasn't prominent enough to gain a third name. It is certain that she had a romance with Lews Therin for a time but that relationship ended a few years prior to the drilling of the Bore. Mierin saw her relationship with Lews Therin as a way to power. When Lews Therin broke off the relationship, Mierin became greatly upset and started to pursue him. About 50 years prior to the War of the Shadow Lews Therin married Ilyena Moerelle Dalisar. This was the breaking point for Mierin, who tried to disrupt the wedding and in the following years made several blatant public attempts and blamed Ilyena for her "losing" Lews Therin.
Mierin, together with another Aes Sedai named Beidomon, was responsible for creating the Bore into the Dark One's prison. This resulted in the destruction of the Sharom and most parts of Collam Daan; Mierin was one of the few survivors. Despite being responsible for drilling the Bore, she was far from the first to swear loyalty to the Dark One. What separates her from her fellow Forsaken is that she chose her own name, Lanfear, which means "Daughter of the Night" in the Old Tongue, on her own, unlike others who were given their names by the ones they betrayed. She claimed Tel'aran'rhiod as her domain and used it in many ways during the War of the Shadow, such as to strike fear in enemy commanders, to drive people insane, to cause suicides and also for outright assassinations. She was never a field commander but she served as governor, at least once, over conquered territories. People that lived in these territories often feared sleeping and the suicide rate was high.
She was one of the Forsaken caught by surprise by Lews Therin Telamon and The Hundred Companions' attack on Shayol Ghul. As a result she was sealed deep within in a timeless, dreamless sleep, preventing her from being affected by the movement of time, unlike Aginor and Balthamel.
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