Trehan Daciano is a member of the royal family of Dacia, the Realm of Blood and Mist . He comes from the House of Shadows in Dacia, the assassin's branch of the royal family. His sole occupation is to take out those who break the laws of Dacia and to assassinate those who leave the kingdom without approval.

Trehan was content with his life until he was sent out to track down Caspion the Tracker. When Trehan located the condemned Death Demon, he found his Bride in the soon-to-be queen of Abaddon, Bettina the Queen of Hearts. Trehan then competed and won the tournament to wed Bettina, but because of a falling out he cast off his winning to Caspion and returned to Dacia.

Trehan returned for Bettina later after receiving advice from his young cousin (considered a niece due to age) Kosmina and king Lotharie.

Trehan has appeared in Lothaire and Shadow's Claim.