Buffy the Vampire Slayer star Nicholas Brendon died from complications tied to cardiovascular disease, with his death officially ruled natural, according to a report obtained by TMZ. The actor best known for playing lovable underdog Xander Harris on all seven seasons of Buffy the Vampire Slayer, has died. He was 54.

The actor was found unresponsive on a couch inside a home in Putnam County, Indiana, on March 20. The coroner determined the cause of death to be atherosclerotic and hypertensive cardiovascular disease — a condition involving significant plaque buildup in the arteries. Officials noted Brendon had a severe 90% blockage in his right coronary artery.

Additional contributing factors included acute pneumonia and a prior heart attack. A friend who had been caring for him told authorities he had suffered a heart attack several years earlier but chose not to pursue further medical treatment.

According to TMZ, the friend said she last saw Brendon around 5 a.m. the day he died and later heard him coughing. When she checked on him again around 8 a.m., he was unresponsive, prompting her to call police. She also told investigators he had recently complained of chest pain but declined to seek hospital care, instead relying on over-the-counter medications.

According to the report, Brendon was a longtime smoker and had been hesitant to seek treatment due in part to a recent back surgery. Surveillance footage from the home reportedly showed him coughing heavily and speaking with a raspy voice in the hours leading up to his death.

Brendon was best known for playing Xander Harris throughout all seven seasons of Buffy the Vampire Slayer, starring alongside Sarah Michelle Gellar.

Throughout his life, Brendon was open about his personal struggles, including battles with depression, alcoholism, and substance abuse. He spoke candidly in interviews about his efforts toward recovery and used his platform to advocate for mental health awareness.

Despite facing legal and personal challenges over the years, Brendon remained closely connected to his fan base and frequently appeared at conventions celebrating Buffy the Vampire Slayer and its enduring legacy.