Actor Nicholas Brendon, best known as Xander Harris on popular 90s teen drama “Buffy the Vampire Slayer,” has died at age 54. Brendon died of natural causes on Friday evening, according to a statement from his family to The Hollywood Reporter. “We are heartbroken to share the passing of our brother and son, Nicholas Brendon. He passed in his sleep of natural causes. Most people know Nicky for his work as an actor and for the characters he brought to life over the years,” the family said before noting that Brendon was not only an actor, but a painter and artist. “While it’s no secret that Nicholas had struggles in the past, he was on medications and treatment to manage his diagnosis and he was optimistic about the future at the time of his passing,” the family added, requesting privacy as they mourn Brendon’s passing. Prior to his breakout role in “Buffy the Vampire Slayer,” Brendon appeared in episodes of “Married… with Children” and “Dave’s World.” After playing Xander Harris in 143 episodes of “Buffy,” he continued acting in TV shows such as “Kitchen Confidential,” “Private Practice,” and in films like “Coherence.” He also served as a TV and film producer. According to IMDb, Brendon has two upcoming projects that are in post-production. Brendon’s “Buffy” co-stars responded to his death on social media.   View this post on Instagram   A post shared by Sarah Michelle (@sarahmgellar)   View this post on Instagram   A post shared by Alyson Hannigan Denisof (@alysonhannigan) Emma Caulfield also expressed her grief in an Instagram Story, sharing a clip from the musical episode of “Buffy”: “I love you, Nicky. Let this clip of us giving it our best be a placeholder. Rest Nicky. Rest.” Brendon suffered a heart attack in 2022, later revealing that he had been diagnosed with a congenital heart condition that caused tachycardia, or abnormally fast heart rate. The TV star also battled mental illness and substance abuse issues, and had multiple run-ins with the law. Brendon entered rehab for the second time in 2010 after “being tasered by police and charged with vandalism, resisting arrest and battery against a police officer. He pleaded no contest and was sentenced to probation and community service,” according to People. He was arrested multiple times over the following years — twice for allegedly attacking his girlfriend — and entered several recovery programs. He was sentenced in 2020 to three years’ probation for one of the attacks, and given 20 hours of community service. Brendon had further run-ins with the law in the years that followed.