ABC Family has added two new cast members to its "Shadowhunters" adaptation series.
Matthew Daddario will play Alec Lightwood and Isaiah Mustafa will play Luke Garroway on the show based on the "Mortal Instruments" series of novels by Cassandra Clare.
Katherine McNamara and Dominic Sherwood were previously cast as the lead characters, Clary Fray and Jace Wayland, respectively. Alberto Rosende and Emeraude Toubia are also on board to play the characters Simon and Isabelle.
"Shadowhunters" will follow 18-year-old Clary, who finds out on her birthday that she is not who she thinks she is but rather comes from a long line of Shadowhunters -- human-angel hybrids who hunt down demons. When her mother Jocelyn is kidnapped, Clary is thrown into the world of demon hunting with mysterious Shadowhunter Jace (Sherwood) and her best friend, Simon.
Daddario's Alec joins Jace and his sister, Isabelle, in their pursuit of demonic creatures. He's tortured by his romantic love for Jace, who is his adoptive brother and fighting partner.
Luke Garroway is an NYPD detective investigating a string of "demonic" murders. Luke feels a fatherly instinct to protect Clary, a strong affection for her mother Jocelyn and has secrets of his own. Once a strong and powerful Shadowhunter, he has since become the thing he once hated most -- a werewolf pack leader.
"Shadowhunters" is produced by Constantin Film and executive produced by Ed Decter and McG, who will also direct the first episode.