From Melissa Marr's website:

Irial (ear ee al)-- This name has obscure/unclear/vague origins and meanings. A short version of his name is "Iri” (eerie) which was just too perfect for his character. He has an interest in tattoos that stretches almost as far back as the art form has existed.

The King of the Dark Court.

On the evening that Keenan reveals himself to Aislinn, starting the Game once more, Ash also encounters Irial. At the time, she is unaware of his name or title: she knows only that he is fey. He enters Pins and Needles, being the third faery powerful enough to be close to, let alone enter, a place filled with iron she has encountered that evening. He even trails his hands over metal, shocking her.

Ash is further startled when she realizes her friend, Leslie, has followed Irial into the tattoo shop. After learning that Leslie thinks Irial is uninterested in her, Aislinn is reassured and she and Leslie don't discuss him during Wicked Lovely.

It is later revealed that Irial and his Dark Court are allies of Beira and her Winter Court, and that Irial helped Beira bind Keenan's powers and created the Curse which requires him to find his Summer Queen in order to tap into the full power of Summer.

Irial is described as "heavily inked . . . beautiful: close-cropped hair, perfect features, blue-black eyes." He is one of three POVs in the second novel, Ink Exchange.