Grant Gustin teases how events from The Flash season 3 will play directly into the way the hero handles his newest adversary, the Thinker. The Flash has seen a number of Big Bads come and go over the last three seasons, but the show hasn't seen anything like season 4's nemesis Clifford DeVoe, who (thankfully) isn't another speedster, but is instead a brilliant tactician, one who forced Barry's return from the Speed Force and caused the event that birthed 12 new meta-humans (aka, the Bus Metas) in Central City.

Needless to say, it is going to take more than the Flash running "faster than ever before" to stop DeVoe and put an end to his plans, but before that can happen, Barry needs to convince everyone else that this seemingly mild-mannered history professor is the real deal. And as Gustin puts it, the seeds about DeVoe that were planted in season 3 are enough to make Barry take this threat seriously very early on in the season.

Gustin talked about DeVoe during a recent set visit to The Flash that Screen Rant attended, and the actor made it clear that the warnings Barry received about the Thinker will effect his handling of the villain, and start to see the hero unravel somewhat and become obsessed. Gustin said:

Kim Engelbrecht as The Mechanic and Neil Sandilands as The Thinker -- Photo- Dan Power:The CW

"Barry starts to get an inkling pretty early that this is somebody pretty serious and we're going to want to nip it in the bud right away. Because of when we heard about this guy and who we heard about him from -- Kadabra mentioned DeVoe to Barry and then Savitar -- Barry is taking it pretty seriously right away... because he doesn't want things to get out of hand again as they always do. So we start to see him unravel slightly for the first time all season. He's been pretty put together this year. He's starts to become a little obsessed with finding this guy and getting everyone to be on the same page and see this is our guy for sure, but everyone else kind of has their doubts for a while."

The events of season 3 weighed heavily on Barry, as it not only revealed a dark possible future where he becomes a heavily armored supervillain from the future, but it also deposited the current timeline version of him in the Speed Force. It's no surprise, then, to think Barry would do anything to keep from having to go through something like that again, and as such, his actions against the Thinker might be more aggressive than the rest of Team Flash is prepared for.

However Barry's course of action plays out, it's interesting to see how the writers have used the name drop of DeVoe during season 3 to influence their main character in the series' fourth go-round. With Barry and Joe set to confront DeVoe directly in 'Therefore I Am' and uncover his backstory, fans (and maybe even Barry) should have a whole new perspective on the season's Big Bad.

Next: Arrow: Oliver Still Hopes to Find Some Redemption for Black Siren

The Flash continues tonight with 'Therefore I Am' @8pm on The CW.