NEWARK, New Jersey: Joe Kubert, a groundbreaking Polish-born comic artist and educator best known for co-creating DC Comics’ iconic Sgt. Rock character, has died. He was 85.

Kubert died Sunday, according to the Kubert School in Dover, New Jersey, which he founded in 1976 to train and teach illustrators and artists. The school did not disclose a location or cause of death.

Kubert co-created Sgt. Frank Rock, a World War II hero with a dangerously accurate shot, an uncanny ability to survive numerous war rounds and who led his patrols with a fierce sense of duty and courage. Kubert also co-created Tor, a prehistoric strongman, and reinvigorated Hawkman, who flew above New York City, fighting crime with a mace.

Kubert was known for his war comics and expressionistic drawings of macho men, muscles rippling as they performed heroics.

“He told stories, he drew stories where you could smell the sweat, you could feel the fear these guys were experiencing as they went into war,” said Pete Carlsson, art director at Tell-A-Graphics, a company Kubert founded.

Kubert was long interested in arts education. In 1976, he and his wife, Muriel, founded the Kubert School as a way to educate aspiring comic book artists and illustrators.

“Joe fostered a portion of an entire generation of cartoonists and storytellers through that school,” said Steve Bissette, an artist who was in the school’s first class.

Bissette remembers watching Kubert working in his studio. Classical music was playing on the radio. Kubert had a brush behind each ear, pen nibs nestled between his fingers, and was quickly switching tools. He drew a cover in about a half hour, Bissette said.

Kubert was born in Poland in 1926. He came to the United States as a baby and grew up in Brooklyn.

Kubert’s life, noted Ivan Brandon, who wrote most of the “Men of War” series for DC last year that featured a relaunched Sgt. Rock, followed the “arc” of the comic book medium and industry. “He was a kid when it started and he did his best to help it grow as he did,” he said. “If you could look back at a single career in American comics to emulate, all the way back to the very beginning, it would be his.”