Agents Of SHIELD Season 4: 15 Characters Who Need To Return

Over its run, countless heroes and villains have come and gone from Agents of S.H.I.E.L.D., some currently MIA and many others losing their lives along the way, never to be seen again. As the show marches towards the final arc of its fourth season - the Agents of HYDRA arc - the time is ripe for many familiar faces from the past to resurface thanks to the existence of the Framework.

The alternate reality of the Framework gives the series the opportunity to bring back any number of long-lost fan favorites from the show's history, from some of the team's most dangerous enemies to many of their fallen allies. With a fifth season still not a surefire thing, allowing these characters to have one last ride in the alternate reality would be a great, fun way to honor their place in the series. That's not to mention all the loose ends still waiting to be tied up in the real world in regards to still-living characters, whose statuses remain unknown.

Putting aside missing characters from the current season that we'll likely see again before it's over, like Ghost Rider, let's take a spoiler-filled look back over the first three seasons to sort out which characters deserve a Framework-related resurrection or a long overdue reemergence in the present day just in case this is the show's final run.

Last Seen: Sinking into the ocean - freezing along the way - after being shot in the second season episode 'Making Friends and Influencing People'.

Gill, the show's version of the comic character Blizzard, has made two appearances on the show, one in each of the first two seasons, with his powers having significantly improved between them. And considering that the show confirmed that his body was never found after he was shot, it's hard to deny that the door has been left wide open for the character's return ever since.

By now, over two years have passed since his last appearance on the show, a time gap that could easily have allowed him to master his abilities even further. Like Calderon, he's a bit of a loose end for the show, and one that deserves to be tied up. If the series does get granted a fifth season, Gill could easily turn up as a solid full-on recurring or one-episode villain, but even if it doesn't, some lip service to what ultimately happened to him - even if he just decided to live a reclusive lifestyle - would be welcomed.