House Tarkanan is a criminal organisation based in Sharn, founded by members of a suicide squad who all had aberrant dragonmarks. They were formed by the Dark Lanterns, and went rogue near the end of The Last War. Since then, they have dwelt in the depths of Sharn, and have gained a reputation for assassination, thievery and other unlawful deeds.
Despite their name, they are not a Dragonmarked House; their name is a parody of the Twelve Houses.