“Hunger Games” actor Mahershala Ali has joined the cast of Marvel and Netflix’s “Luke Cage” series, the companies announced Thursday. Ali will play Cornell “Cottonmouth” Stokes, a villain right out of comic book pages. In this iteration, Stokes is a Harlem nightclub owner who will become an unexpected foe in Luke’s life when Stokes’ criminal activities threaten Luke’s world. Mike Colter stars on the third collaboration between Marvel and Netflix, following “Daredevil,” which aired earlier this year, and “Jessica Jones,” which will be released in the fall. Colter’s superhero alter-ego will first appear on “Jessica Jones,...