Henry Ian Cusick, Tanya Clarke, and Michael Biue have been cast in ABC's Inhumans, according to IMDB. Clarke and Biue will reportedly play Queen Ryanda and King Agon (Black Bolt's parents), while Cusick is slated to play a new character, Dr. Evan Declan. While an IMDB listing is not a definite source for casting, its reliability in the past is worth noting.
Cusick is best known for playing Desmond Hume in ABC's Lost - which like Inhumans, was filmed primarily in Hawaii. The Peruvian actor currently co-stars in The 100.
Clarke's most familiar role was that of Emily Lotus in Cinemax's Banshee, while Buie is best known as Grey's Anatomy's Paul Dawson.
The two-part series premiere of Inhumans is scheduled to debut September 1 in IMAX theaters, before seguing to its normal television airing beginning September 22 on ABC.