In 2009, there were faeries crossing over into the mundane realm apparently tricking humans into eating faerie fruit. This could entrap humans with faeries or to the Faerieland, but, according to Jon Cartwright, this can also result in their death. In response, second-year students from the Shadowhunter Academy were sent to Devon, where they were last spotted, to stop them.
Hefeydd was among the faeries that arrived at the moor. Hooded and cloaked, Hefeydd carried the basket of fruits and had reinforcements with him, in paranoia due to the Cold Peace. The Ascendant George Lovelace pursued him as he was escaping back to the Faerie, and Lewis, in an attempt to stop his friend, was accidentally brought into Faerieland.
Hefeydd then imprisoned Simon in a cage in his quarters, but when respected Wild Hunt member Mark Blackthorn came to investigate, since the horse Simon was on when he stumbled into the path to the Faerie ran into the path of the Wild Hunt, Hefeydd agreed to let them speak and even drop his claim on the would-be Shadowhunter if it meant not being in trouble with Gwyn ap Nudd. However, when the "prince" Kieran arrived and took Mark away, Hefeydd once again had Simon to himself. Under Mark's orders, he offered Simon water, which Simon knew better than to drink as it could enslave him. Instead, Simon pretended to drink and pick-pocketed the key to his cage hanging from his cloak.
With the key, Simon was able to open the cage but remained shortly to be with Isabelle Lightwood, who had arrived to get him out. Hefeydd caught them and locked both in, forcing Izzy to surrender her tools and weapons, as well. The couple again managed to escape since Isabelle had secured the key.
Hefeydd had large, purple-tinted ears and long white hair.
- Bitter of Tongue (first and only appearance)