Arrow Season 3 Finale Spoilers: Showrunner Marc Guggenheim Says It Could Be 'Series Finale'

The Season 3 finale of Arrow airs tonight, and while fans know that the show is coming back for Season 4, showrunner Marc Guggenheim refers to the episode as a "series finale" in a new interview.

Now obviously the show is not ending for good tonight, so let's allow Guggenheim to explain.

"It comes to a pretty definitive conclusion," he told E! Online. "By the end of the finale, you know exactly where Oliver stands. You know why Oliver's done what he's done. You may not agree with it, as some characters don't, but it's a very definite end. In fact, it's so definitive that on some levels, the episode can play as a series finale."

By now, most fans know that Grant Gustin appears on tonight's episode as The Flash, and Guggenheim addressed his importance to the finale.

"He factors in pretty huge. Basically, the whole episode really could not happen without Barry's involvement," he said. "The tricky part of this shared universe is the fact that the characters are all within one phone call of each other. So what's to prevent Team Arrow from calling Barry every time they need help? We address that pretty head on in the finale."

If you watched The Flash last night, then you know that Oliver told Barry he would need a favor from him. It looks like he'll call in that favor tonight.

Finally, Guggenheim talked about the Season 3 finale in the grand scheme of the show and what it means for Season 4.

"It's more present day than flashbacks. The flashback story gets its own conclusion. Each season finale of Arrow in the present day story has been a little different," he said. "Season one ended in Tommy's death and a loss for Oliver. Season two we ended with this huge win for Oliver. Season three, we wanted to try something a little different. I think it's the more cliffhanger-y of all the finales we've done. It's not whether or not Oliver lives or dies, because everyone knows the answer to that. But it is a cliffhanger in the sense of, the end will have everyone wondering how the show can even go on. How can we bring the show back for season four after these last five or six episodes."

What do you think will happen on tonight's episode? Let us know in the comments section.