Stan Lee, the co-creator and writer of Marvel Comics, died on Monday in Los Angeles at the age of 95, according to The New York Times.  A slew of celebrities including actor Winston Duke, director James Wan and NBA superstar LeBron James shared their condolences on social media.

Kirk Schenck, an attorney for Lee’s daughter, Joan Celia, confirmed his death at Cedars-Sinai Medical Center.

Lee was born in New York City in December 1922. At 17, he began his career in comics at Timely Comics, a division of Martin Goodman’s publishing company.

Timely later developed into Marvel Comics with the birth of The Fantastic Four in November 1961.

The 95-year-old remained a figurehead at the Marvel for more than five decades. Even after his retirement, he continued to give lectures and make cameos in all of the Marvel movies.

The comic book writer is best known developing legendary comic characters in the Marvel Universe, including the X-Men, Spider-Man, Thor and Black Panther. Through his leadership, many of these superheroes and villains became prominent staples in pop culture and the subjects of blockbuster movie franchises.

Lee introduced complex and nuanced superheroes to the world. Prior to his creations, the superhuman characters of comics were perfect.

In February 1992, he told The Washington Post, “I tried to make them real flesh-and-blood characters with personality, which should not be considered radical.”

He continued, “That’s what any story should have, but comics didn’t up to that point, they were all cardboard figures. Make them real, give them personality. Give them problems.”

Lee also used his comic books to give social commentary on issues such as racism.

“The only things we don’t have room for are hatred, intolerance and bigotry. That man next to you? He’s your brother. That woman over there? She’s your sister,”  he said in a clip shared by NBC anchor Carl Quintanilla.

Lee was inducted into the Will Eisner Award Hall of Fame in 1994. He also received a National Medal of Arts in 2008.

Check out what celebrities had to say about Lee’s legacy and impact below.

LeBron James

Dwayne “The Rock” Johnson

Winston Duke

Chris Evans

Travis Scott

Lloyd Banks

Letitia Wright

Rosario Dawson

Ryan Reynolds

Darryl McDaniels of RUN DMC

Angela Bassett

Zoe Saldana

Zuri Hall