Warning: Agents of S.H.I.E.L.D season 2 spoilers ahead
Come season 3, Agents of S.H.I.E.L.D will be adding Luke Mitchell and Henry Simmons as series regulars. Both held guest star positions during season 2. Simmons played Alphonso “Mack” Mackenzie, a S.H.I.E.L.D agent. He developed a close bond with fellow S.H.I.E.L.D operative Leopold Fitz (Iain De Caestecker), who suffered brain damage after Agent Grant Ward (Brett Dalton) revealed himself as a HYDRA agent during the Winter Soldier tie-in episode.
Mitchel portrays Lincoln Campbell, an Inhuman working as a guide in Afterlife. He has the power to manipulate the electrical charge in molecules, which grants him abilities such as shooting out electrical bolts and levitation. He befriends Skye (Chloe Bennett) after she arrives at Afterlife. At the end of season 2, he allies himself with S.H.I.E.L.D against the Inhumans, led by Skye’s mother Jiaying (Dichen Lachman).