[Photo provided to China Daily]

An 11-year-old mutant then shows up, disturbing Wolverine's weary life. At the end, Logan's glorious yet tragic end comes.

"When the credits were rolling (at the 67th Berlin International Film Festival), I couldn't imagine a more perfect way to end our story," says Stewart, who also decided Logan would also be his last movie as Professor X.

At the end of Logan, all the mutants, including Wolverine, die to protect the young.

At the age of 76, Stewart injects his pondering about life philosophy into the cinema.

"Mortality is a reality. We do not live forever. We simply do the best we can, but it's important for others. That's how civilization evolves," says Stewart, speaking about his last days as Professor X.

With an ambition to be more than a popcorn hit, Logan explores humanity, death and love.