SPOILER ALERT: This story discusses major plot developments in Season 2, Episode 1 of “Peacemaker,” currently streaming on HBO Max. When James Gunn first premiered “Peacemaker” in 2022, the spin-off series for his 2021 feature film “The Suicide Squad” stood apart with its blue-collar, human-scaled, TV-MA-rated lens on a superhero story. The first season followed the titular lead, a.k.a. Christopher Smith (John Cena), as he transformed from an emotionally stunted, morally flexible killing machine into a complex hero filled with remorse for his past bad deeds. Along the way, the show deployed prolific profanity and extravagant blood and gore, but...