James Hetfield declared in an interview with Metal XS:
"Kirk was not part of the writing. Kirk obviously came in and did the solos. But Lars and I… You know, Lars and I always have done this, but with contributions from other people on their riffs and things. Kirk's riffs weren't there. I know he talks about him losing his phone and things like that with the riffs, but… No, he wasn't involved in the process. And Robert was there. The intro to 'ManUNkind' is Robert; that is him, and it's beautiful. But it is Lars and I doing what we always do, put the songs together.