Lucas Sinclair

Lucas Sinclair, portrayed by Caleb McLaughlin, is a main character in Stranger Things. He is the ex-boyfriend of Max Mayfield and the best friend of Mike Wheeler, Dustin Henderson, Will Byers and Eleven.
In 1983, Lucas's friend, Will mysteriously vanished so Lucas and the rest of his friends, Mikeand Dustin went out to look for him, only to meet a girl named Eleven who had telekinetic powers. Lucas was wary of Eleven and found her weird and hardly believed in supernatural circumstances of Will's disappearance. However, when Lucas realized that Eleven was trying to protect him and his friends from the dangers of Hawkins National Laboratory and the Upside Down, his opinion of her changed and he became good friends with her. Lucas continued to help his friends and battle the Demogorgon until it was killed by Eleven. In the end, Lucas was reunited with Will and celebrated Christmas with his friends.
In 1984, following Max's arrival at Hawkins, he developed feelings for her, eventually forming a special bond with her. At the end, he and his friends assisted as a distraction to burn the Mind Flayer's external core for Eleven to close the Gate for good. A month later, Lucas attended his school's Snow Ball with his friends and started a romantic relationship with Max, as they danced and shared a kiss.
A year later, in 1985, Lucas is still head over heels for his girlfriend, Max, but when Mike and Eleven's relationship falls out, Max ditches Lucas to hang with Eleven instead — forcing the group to split up. When Lucas and his friends discovered the Mind Flayer had returned to Hawkins and started possessing people, including Max's stepbrother, Billy Hargrove, Lucas protected his friends and fought the Mind Flayer as it sought revenge on Lucas and his friends. Three months later, after the Mind Flayer's defeat, Lucas said goodbye to Will and Eleven as they moved away from Hawkins, before he and Dustin give their Dungeons & Dragons set to Lucas's little sister, Erica.
In the spring of 1986, Lucas is a benchwarmer on the Hawkins High basketball team, and his busy schedule gets in the way of his time with Hellfire Club, much to his friends Dustin and Mike's chagrin. Tired of being bullied, Lucas hopes that joining the basketball team will make him more popular. He's worried about his ex, Max, but she refuses to open up to him. Yet, after the mysterious death of the girlfriend of one of his basketball teammates, Lucas began to realize he had been hanging with the wrong crowd. Reuniting with his friends, Lucas learned of an entity named Vecna who was opening portals to the Upside Down by contact with the people he murders. In an attempt to stop Vecna, Lucas fought his former friend, Jason and nearly lost Max in the process before she was placed in a coma, leaving Lucas to visit her in the hospital.