Agents Of SHIELD: 10 Characters Who Should Return In Season 4
5. Sam & Billy Koenig
Last Seen: Billy went away to "recharge his batteries", while Sam was sent by Coulson to enact the Theta Protocol in 'What They Become', the second season's midseason finale.
This two-for-one deal - or three-for-one, if you count their late brother Eric - always proved hilarious in their appearances throughout the show. Patton Oswalt nails the roles, and their glaring absence throughout all the crazy events of season three was impossible not to notice.
Considering that Ward murdered Eric in season one, it was surprising that the two surviving brothers didn't play a part in the first half of season three to help bring him down at his most dangerous. Their interplay with the other characters frequently provided levity, and with S.H.I.E.L.D. itself having seemingly gone through a restructuring during the six-month time jump we left the season off on, it'd be nice to see the agents back in the fray keeping everyone in line about wearing their lanyards.