Logan: 12 Theories That Were Utter Bull
11. Richard E. Grant Is Really Playing Mister Sinister
The Theory: Richard E. Grant's role in the film was kept fiercely under wraps for a long time before finally being confirmed to be Dr. Zander Rice, but even then, many fans still believed they were being hoodwinked, and he was in fact playing the supervillain Mister Sinister.
The Truth: Grant does indeed play Rice in a relatively small role, and the movie makes no direct references to Sinister at all, despite previous claims from Bryan Singer that he would show up in some form.
Director James Mangold ultimately vetoed a Sinister cameo as he felt it wouldn't be tonally consistent with the rest of the story, and that really seems like the right call here.
Also, don't expect to see Grant again, because Logan puts a bullet through Rice's head in the third act. He's done.