Erawan is the King of the Valg and the main antagonist of the Throne of Glass series.
Until Empire of Storms, Erawan had inhabited Duke Perrington's body, and therefore took on his appearance.
However, in Empire of Storms, Erawan officially sheds Perrington's body and shows his true form. He is described as an incredibly beautiful man with ivory skin, golden-blonde hair and brilliant gold eyes identical to Manon's.
Erawan, as the last remaining Valg King, is very malicious and cold. Although he is physically beautiful, Manon notes him to be very cruel and demanding, and he is absolutely ruthless in his plans to take over Erilea.
Erawan makes his first official appearance in Empire of Storms. He hid as Duke Perrington since Throne of Glass, but he now appears as himself. This surprises Manon and her Grandmother when they meet with him as he looks completely different from the man they originally worked with. He claims that his enemies know who is is, so there is no sense in hiding anymore.
During the meeting, he demands that Manon lead the Ironteeth Witches in an attack on Rifthold and tells Manon to bring Dorian to him if he survives.