Guardians of the Galaxy was a significant film for Marvel Studios for a number of reasons. Not only was it a serious departure from what had come before, but it also marked the first proper introduction of the MCU’s Big Bad, Thanos. Josh Brolin inhabited the role via motion-capture for writer/director James Gunn’s sci-fi epic, and while Thanos didn’t have a ton of screentime in the movie, his presence loomed large.

Naturally, since he hasn’t made another appearance in the MCU since (aside from the Age of Ultron tag), when it came time to talk Guardians of the Galaxy 2 fans were curious if Thanos would be back. The answer is a resounding “No,” with Gunn himself rather pointedly saying that Guardians of the Galaxy, Vol. 2 is very much its own story, and thus had no need for Thanos to come in and tie things into the larger MCU as a whole.

But what was the decision-making process that led to excluding Thanos from Guardians 2? This question was posed to Gunn last year when Collider’s own Perri Nemiroff visited the set of the sequel in Atlanta. Here’s what the filmmaker had to say about why Thanos isn’t in Guardians of the Galaxy, Vol. 2:

“It’s about two sisters. It’s not about the sisters and their father. It’s about two sisters and what were the sisters’ problems with each other? And, you know, some of those things were caused by being raised by the ultimate abusive father. But it really isn’t about Thanos, and frankly, I just wasn’t inspired to put him in the movie. You know, I kind of go with my gut on these things and it just wasn’t what I wanted to do. It wasn’t the most fun part of the movie last time for me and I just didn’t really wanna do it this time. And again, the relationship with Thanos has nothing to do with it. It’s not about their relationship with Thanos. It’s about their relationship to each other, and what is that? And that was interesting to me, and I thought that was important to our story, and that was important to our characters. What happened with them in the past—there’s a lot of stuff that happened with them in the past that affects our characters presently.”

So it sounds like the focus will be on Gamora (Zoe Saldana) and Nebula (Karen Gillan) without their father in the picture to muck things up. That’s actually pretty sound reasoning, and it’s far more interesting to see this relationship play out without cutting to this giant purple CG dude every so often.

But while Thanos was never really considered for Guardians 2, another character was. During the same set visit, Gunn revealed that he had another major character as part of the Guardians of the Galaxy 2 ensemble in the treatment phase:

“One major thing that happened during the treatment phase— not even during the script phase, during the treatment phase— there was another character that was a major character that was a part of the treatment. And although it kind of worked generally in the story, I got to the place where there were too many characters. There’s been other movies that have come— I think Civil War has a lot of characters really well, but they’re minor characters and in this movie every character kind of has their own arc, their own thing, and I thought it was one character too many so I took one of the characters out of the story about halfway through the treatment phase.”

We know Guardians 2 introduces Mantis (played by Pom Klementieff) to the ensemble, as well as Kurt Russell’s Ego the Living planet, and that’s not to mention the return of Nebula and Yondu (Michael Rooker). So it makes sense that adding yet another major character would leave you with a crowded movie. But beyond this change, Gunn says the shooting script is quite close to his initial treatment:

“The eventual 70-page treatment, which is what it was, is what this movie is, and it has changed very, very little. There have been almost no changes in the past three or four months before shooting. Minor, minor lines here and there. We did rehearsals and some things I changed because of that, but I think in terms of a Marvel movie, I think it’s extraordinarily—now, who knows? We might go into post and go, ‘Oh my God, let’s change everything.’ [Laughs] I hope that isn’t the case, but I’ve been really fortunate. And part of it is because I knew on the last movie, we did do a lot of changes later on. We did some changes in production, we did some changes in post-production, and I knew this time I was really fortunate to have such a head start on the script and to make that story really strong so that we could have that from the beginning. And so that was something I focused on, was really dialing in the screenplay, the dialog, everything before we ever even came here to Atlanta.”

Indeed, Gunn started writing the treatment for Guardians of the Galaxy, Vol. 2 the weekend that the first Guardians came out, so he certainly had a lot of lead time to develop and hone the screenplay. But as he points out, Marvel movies are famous for adding and refining things during post-production, so it’s possible changes are ongoing as you're reading this.

For more on Guardians of the Galaxy, Vol. 2, peruse all of our set visit coverage in the links below. The film opens in theaters on May 5th.

• 'Guardians of the Galaxy Vol. 2: 40 Things to Know from Our Visit to the Set
• 'Guardians of the Galaxy Vol. 2': Chris Pratt on How the Power Stone Comes into Play
• Kevin Feige on How 'Guardians of the Galaxy Vol. 2' Connects to the Larger MCU
• Thanos Is the Main Character in 'Avengers: Infinity War', Says Kevin Feige
• Go Behind the Scenes of 'Guardians of the Galaxy Vol. 2' with New, Action-Packed Images