In fact, the 36-year-old filmmaker wasn't even sure if he would move forward without Boseman. His mind ran "the whole gamut," Coogler told Yahoo Entertainment ahead of the release of sequel he ultimately made, Black Panther: Wakanda Forever.

"Because the first thing you're dealing with is shock. Then coming out of shock, I didn't want to feel how I was feeling, if that makes sense. So I thought a lot of irrational thoughts. But thankfully I had the time to let those thoughts pass and reflect, and think about what was right, and what he would want. There's no way I could call him and ask him. But thankfully he communicated what he wanted to tell us through his actions. And I was trying to listen to that, and interpret that, and made the call to keep going," he said.

Marvel producer Nate Moore confirmed that after Boseman's death from colon cancer at age 43, a battle the actor kept intensely private, there existed a real possibility that the studio would shelve its planned sequel.

There were "conversations of 'Does it even make sense to do another movie? Maybe it's a one-and-done.' But I think, and I know from talking to other people, that he wouldn't have wanted that. Because he, almost more than any of us, understood what Wakanda meant to people," Moore said. "And I think even before us, understood what it could mean to people when we were making the first film. So then it became, 'Well, what's the story that we as storytellers can believe in and pour ourselves into?'"

Co-written by Coogler and Joe Robert Cole, the deeply emotional Wakanda Forever is steeped in art tragically imitating life. The film opens with the brilliant-minded scientist Shuri (Letitia Wright) frantically attempting to harness the Heart-Shaped Herb to help save her brother's life. Offscreen, though, King T'Challa (Boseman) perishes from an undisclosed illness, sending Wakanda — and the world — into mourning.

Even as a conventional Marvel adventure plot soon emerges involving the threat of a powerful underwater kingdom called Talocan, its characters continue to grieve — just as the actors who played them did on the film's Atlanta set.

"It was tough because you're trying to figure out your emotions as you're going through pre-production," Wright says. "You're like, 'How do I place how I’m feeling?' And I feel like the way that Ryan, with sensitivity, created this script, and allowed for us to follow that journey of those raw emotions, allowed us to place those real emotions in real life.

"It was tough, man. Somedays you're like, 'Can we just snap and wake up? This has to be a dream. And you just feel this gentle hand pushing you forward. And it's bro [Boseman] being like, 'You could do this. One day at a time, you can do this.' And I think it's just us laying our hearts out for him into this film. How we care for him, how we miss him. We just pour it all into this film."

The experience of making Wakanda Forever, which proves a deeply felt tribute to the late actor, then became cathartic for its close-knit cast.

"It was the only way, man," says Lupita Nyong'o, who plays Nakia, T'Challa's confidant and love interest. "When Ryan walked me through the new story once Chadwick had passed, I was so relieved I wept out of pure relief that we didn't have to pretend like he hadn't died. The story very much embraced that loss, and made use of our grief. So we could still be going through the stages of grief in our life and use it for this art form. And so it felt like art imitating life in the most therapeutic way."

"It was also scary, because you want to make sure [it's a tribute]," says Danai Gurira, who returns as Dora Milaje leader Okoye. "And you want to make sure that you're giving your all in that regard, like you're honoring him with everything that you're doing and every way that you bring the story to pass. There was a displacement, a disorientation to step into this process without him. And you could feel that."

Adds Nyong'o: "The thing that I was most afraid of in going back to Wakanda became the way that I healed. The way that I moved forward was by going to Wakanda. So what I dreaded was exactly what I needed."