Keith Giffen, the comic book artist and writer who created characters now beloved of cinemagoers, has died aged 70.

Giffen, born in Queens, New York, in 1952, is best known for his work for both Marvel and DC. Among the many characters he created were Rocket Raccoon, star of Marvel’s Guardians of the Galaxy movie series, and the DC superhero Blue Beetle, AKA Jaime Reyes, a Mexican-American iteration of a longstanding character, who this year had his own film outing.

Giffen died on Monday, reportedly after suffering a stroke at his home in Virginia Beach, Virginia. Paul Levitz, a comics writer and former president of DC comics, said on his Facebook page early Thursday morning: “The sad news is now official: Keith Giffen has gone off to create new worlds that are beyond our living reach. Keith was probably the most fertile creative mind of our generation in comics. He had an infinite number of ideas, pouring constantly out.”

Giffen started his comics career working for Marvel in the 1970s, but he is best known for his work for DC in the 1980s and 1990s, especially on books with big ensemble casts such as the far future-set Legion of Super-Heroes and Justice League.

The latter series, with co-creators JM DeMatteis and Kevin Maguire, perhaps best showcased Giffen’s gift for comedic writing and injecting an almost soap opera mentality into superhero books.

Justice League, later Justice League International, had an almost prescient, real-world tone, with a maverick millionaire capitalist, Maxwell Lord, essentially staging an Elon Musk-style takeover of the superhero team, getting them United Nations funding and government approval.

The personal interactions of the characters were just as important, and the series came across more like Friends than the usual superhero fare.

Giffen’s humour endured until the very end. A message breaking the news, thought to have been pre-penned by Giffen himself, appeared on his Facebook page on Thursday morning. It said:

I told them I was sick … Anything not to go to New York Comic Con
Thanx. Keith Giffen 1952-2023.

New York Comic-Con begins today and tributes are expected to be led by DC executives on their panels at the event. Giffen signed off the message: “Bwah ha ha ha ha” – the distinctive laughter used in Justice League, especially by the constantly bantering characters Booster Gold and Blue Beetle.

Although not at the level of his 80s-90s heyday, Giffen continued to work in comics and remained a major figure in the industry – he also produced a weekly comics podcast, titled with typical gallows humour, “I’m Not Dead Yet!”.

Many in the comics industry posted their tributes to Giffen on social media. Longtime collaborator DeMatteis wrote on X (formerly Twitter): “Keith was one of the most brilliantly creative humans I’ve ever known. A curmudgeon with a heart of gold. A generous collaborator. An old, dear friend. And, as my wife observed, ‘He was like a character out of a Keith Giffen story’.”

Artist Colleen Doran wrote: “My very dear friend, one of the best friends I have ever had. Keith Giffen. I am heartbroken. I will love you forever. You were endlessly kind and crazy, funny and awful, beyond smart, truly original.”

Writer Gail Simone tweeted: “Spending half an hour with him meant hearing so many original ideas it made you dizzy. Everyone told me he could be crabby, instead, he was lovely and generous to me every time we talked. I will always be a fan and carry awe for that man.”

And Scottish writer Mark Millar added: “So many great Keith Giffen comics to remember him by, but for me it was Ambush Bug, which I absolutely loved as a kid. But his Action Comics, Lobo and of course Justice League just some of the best titles ever. RIP to an absolute legend.”