As fans have noted from early on, in the main portion of "The Wolverine" is based on the character's first standalone miniseries by Chris Claremont and "Sin City" creator Frank Miller. And while director James Mangold wanted to pull from the beloved classic, which tells the story of Wolverine in Japan, he also added another theme that fascinated him.

"I read the Claremont-Miller when it came out, and I loved it. I loved the world of it," Mangold told MTV News' Josh Horowitz . "The only thing I tried to bring to it was this idea, this theme about his immortality and about the idea of what it is to live forever."

Mangold's interest in immortality stemmed from a few sources, but the reason behind his fascination applied easily to the plight of Wolverine.

"I thought this is such an interesting aspect to this character," he said. "He's been alive almost 300 years and the exhaustion and pain of making connections with people and losing them. Not only has he been betrayed by nature and betrayed by science, but he's betrayed by love, because every time he loves someone, they end up dead or just fade away."

The film's opening -- Wolverine living alone in the Canadian wilderness -- was what Mangold felt most inspired to take straight from the comic book, but again, he wanted to shift it in a way that felt natural for the character. "Finding Logan in the woods alone, finding him as a ruminating alienated mountain man, I thought, was really evocative to me, the place that that saga started, because it made me think, 'Why has he estranged himself?'"

The director also decided to shift the originally planned timeframe of the film, as it was supposed to take place in between "X-Men Origins: Wolverine" and the rest of the series.

"Everyone assumed that it took place in the middle of the timeline of Wolverine and X-Men movies," he said. "It was my assumption that this took place after everything I had seen. The fusion for me was finding this guy in the woods who has lost everything."

As inspired as Mangold was by the Claremont-Miller take on Wolverine, he didn't suggest that the actors read it before diving into production.

"You tell someone 'Don't do this,' they'll do it. When I made 'Walk the Line,' the thing I told Joaquin Phoenix every day, and he'd even come to set and say 'Say that thing.' I'd go, 'You're not Johnny Cash,' " Mangold said. "The biggest thing you can do to someone is just liberate them. In order to do the best job for the character and for the preexisting material, you almost have to liberate the actor from the burden of imitating something. You have to let them be it, not imitate it. He's done this role so many times. I just wanted to take him further inside, and I felt that he didn't even have the airtime in many of the movies to explore, let alone the tone."

"The Wolverine" is in theaters now.