Len Wein, the comic book writer and editor who co-created popular superheroes such as Marvel’s Wolverine and DC Comics’ Swamp Thing died today at the age of 69. DC Comics confirmed the news on their website.

“Len Wein was one of the most welcoming people and legends in comics from the moment I joined DC eight years ago,” wrote Diane Nelson, President of DC Entertainment. “He wrote or edited almost every major DC character – there’s hardly a facet of DC’s world that Len didn’t touch. I, DC and the industry will miss him and his talent very much. Our love and prayers go out to Christine, his family and his fans.”

Wein was born on June 12, 1948. He and his friend Marv Wolfman published their own fanzines and sold their first scripts to DC in 1968. He received praise for his work on The Teen Titans and co-created Swamp Thing with artist Bernie Wrightson, which became one of DC’s most iconic characters. Swamp Thing was adapted into a Wes Craven film in 1982 and was followed by a sequel, The Return of Swamp Thing, in 1989. In 1990, Swamp Thing made its way to the small screen for a television series on the USA Network. The series ran until 1993.

During the ’70s he worked for Marvel. While there he co-created Wolverine with artists John Romita Sr. and Herb Trimpe. The character has since become one of the most popular comic book heroes and X-Men character. Hugh Jackman, who has played the character since 2000’s X-Men through 2017’s Logan took to Twitter to send his condolences.

In the 1980s, he edited Alan Moore’s acclaimed series Watchmen, which was adapted for the big screen by Zack Snyder in 2009.

“Not every writer can be a good editor,” said Geoff Johns, President & Chief Creative Officer of DC Entertainment. “But Len deserves equal credit for both talents. He helped to revitalize the entire DC Universe.”

Wein was inducted into the Will Eisner comic book hall of fame in 2008.