"The Flash" season 2 ended with Harrison Wells/ Eobard Thawne (Tom Cavanagh) getting pulled out of existence when his ancestor Eddie Thawne (Rick Cosnett) shot himself, preventing Eobard from ever being born in the future. However, the finale also hinted at possible timelines, meaning a different Harrison Wells still exists. 

According to a report from Cinema Blend, actor Grant Gustion, who plays Barry Allen aka the Flash, stated during the 2015 San Diego Comic-Con that Harrison Wells is still in the show but that this is not the same Wells from season 1. The actor continued to explain that they won't be interacting during the premiere episode because they haven't even met yet. This would indicate that this is a different Harrison Wells from  a different timeline.

The show has already delved into the concept of a multiverse when Cisco (Carlos Valdes) was brought back to life when the Flash reversed time but was still aware of the events that occurred in the previous, parallel universe where he died. 

"Wells is on the show, but we're introducing the multiverse concept, so that's why he exists still somewhere," the actor stated during the SDCC panel. 

If this is the case, then this Harrison Wells might be the real Harrison Wells, one that Eobard Thawne did not kill and impersonate. If true, then this version of the character might be brought on as the new mentor for the crew. It is also still possible that this is a Wells from another dimension where Eobard still managed to kill and impersonate him. 

Another hint that season 2 will explore the multiverse is that Teddy Sears, popular for his role in "Masters of Sex," has been cast as Jay Garrick. Garrick's helmet was seen in the season 1 finale and fans of the comic books identify him as the Golden Age Flash or the Flash of Earth-2.

"The Flash" season 2 premieres on Oct. 6.