Logan Trailer Breakdown: 24 Things You Need To See
16. Stephen Merchant As Caliban
A lot of eyebrows were raised when it was revealed that Stephen Merchant had won a supporting role in the movie, and it was revealed a few days before the trailer drop that he'd be playing Caliban, the mutant with the ability to track other mutants (and who actually appeared briefly in X-Men: Apocalypse, albeit not played by Merchant).
It seems that he may have been hired to locate Logan and Laura, but an extremely brief shot at the end of the trailer shows Caliban being manhandled by the Reavers, perhaps suggesting that he's instead pursuing Logan to warn him rather than hurt him.