Tomorrow night, HBO will air the eighth Season 6 episode of Game of Thrones, entitled No One at 9 PM ET. Last week, plot details and photos were released for this upcoming episode, and, as has been the case all season, they don't reveal too much about the story. However, a new image has surfaced that may tease the return of a character thought to have been killed way back in Season 1. If you aren't caught up on Game of Thrones, there will be SPOILERS below, so read on at your own risk.

Towards the end of last week's episode The Broken Man, Arya Stark was seen booking passage back to Westeros, after she couldn't complete her mission for her mentor Jaquen H'gar (Tom Wlaschiha). Arya is then approached by what appears to be an elderly woman, but is really The Waif (Faye Marsay), who stabs Arya in the gut several times before Arya made her escape by jumping off the bridge. Arya was last seen bleeding profusely, walking through the streets of Braavos.

RELATED: First Official Game of Thrones Convention Is Coming in 2022

We got a brief glimpse of The Waif in the preview for No One, before a new photo emreged, showing The Waif again, presumably looking for Arya in Braavos. However, a Twitter user reveals that this photo may also tease the return of Arya's swordsman mentor, Syrio Forel (Miltos Yerolemou). In the background, behind The Waif, the shadow of a figure is seen, which certainly does resemble Syrio, even though we can't see this person's face. Syrio was presumably killed towards the end of Season 1, after telling Arya to flee from King's Landing when King Joffrey (Jack Gleeson) beheaded her father Ned (Sean Bean), and Syrio was never seen or heard from again.

It's worth noting that fans never actually saw Syrio Forel die in the first season, as he was last seen dueling with Meryn Trant (Ian Beattie), who Arya actually killed at the end of Season 5, a killing she was punished for by being turned blind by Jaquen H'gar. Showrunners David Benioff and D.B. Weiss have previously stated that Syrio is dead, but they also said that about Jon Snow (Kit Harington) and he ended up coming back from the dead. It's also possible that this isn't Syrio at all, but Jaquen H'gar using Syrio's face. We'll have to wait and see.

If this mysterious person is actually Syrio Forel, he will be just the latest in a string of characters who have either been brought back from the dead, or are returning after lengthy hiatuses. Of course, Jon Snow is the most prominent figure to be resurrected, but we also learned in last week's episode that the presumed-dead Sandor "The Hound" Clegane (Rory McCann) is actually alive and well. This season has also brought the return of Bran Stark (Isaac Hempstead Wright), Hodor (Kristian Nairn), Meera (Ellie Kendrick), Rickon Stark (Art Parkinson), Osha (Natalia Tena), Yara Greyjoy (Gemma Whelan), Walder Frey (David Bradley) and Benjen Stark (Joseph Mawle), just to name a few. While we wait for tomorrow night's episode, check out this photo below which hints at Syrio Forel's return.

Game of Thrones Season 6 Photo