A survivor who absorbs energy and gives it back, and the man the resistance sends back in time before Wolverine.
Lucas Bishop is a mutant who can harness and redirect energy, notably through his gun, and one of the surviving mutants in the future. Omar Sy plays him.
The film opens by showing that the resistance already has time travel, in small doses: Kitty Pryde sends Bishop back a few days so the group can avoid an attack that already killed them. The whole plot is that same trick attempted at a distance of fifty years.