Ólafur Darri Ólafsson; 'How to Train Your Dragon' Jónatan Grétarsson/Universal EXCLUSIVE: Universal’s sequel to its live-action hit, How to Train Your Dragon, is gearing up fast as sources tell Deadline Ólafur Darri Ólafsson is set to join the cast in the role of Drago. He joins returning castmembers Mason Thames, Nico Parker, Gerard Butler, Julian Dennison, Gabriel Howell, Bronwyn James and Harry Trevaldwyn in the sequel with Cate Blanchett recently added as a new addition to the cast. Dean DeBlois returns to write, direct and executive produce the next entry in this iconic franchise.