Comic book creator Carlos Pacheco has died at the age of 60, Spanish news sources have confirmed.

Carlos Pacheco, best known as an artist for both Marvel and DC across the past three decades, initially broke into the comics industry working for Planeta-DeAgostini Comics, a Spanish-Italian publisher specializing in reprints of American material. His first superhero comic book work appeared in that company’s Marvel Héroes #41 in 1991, before he went on to co-create two miniseries featuring original characters with writer Rafael Marín. That work would catch the attention of editors at Marvel UK, who quickly brought him onboard the nascent Overkill line of titles it was creating at the time.

Pacheco's clean-lined, dynamic work on titles like Dark Guard would swiftly win him gigs at both Marvel and DC, with fill-in work on Mark Waid’s Flash run at the latter and a run of issues for Marvel’s X-Men office, including the four-issue Bishop miniseries in 1994, as well as the two-part X-Universe mini created as part of the fan-favorite Age of Apocalypse crossover. From that point on, he was a regular in Marvel’s line, illustrating issues of Fantastic Four, Excalibur, and X-Men, before teaming with writers Kurt Busiek and Roger Stern for the acclaimed Avengers Forever miniseries; that mini would also see Pacheco’s pencils inked by Jesus Merino for the first time, forming a creative bond that would go on for years.

Following an all-too-brief run on the Fantastic Four franchise — first on a 2000 Inhumans miniseries that saw him work with Marín again after a number of years, and then on the main Fantastic Four series, where he co-wrote (initially with Marín, and then with Jeph Loeb) and illustrated — Pacheco returned to DC, where he primarily worked with Kurt Busiek, on the creator-owned Arrowsmith series as well as the main Superman title, and Geoff Johns, with whom he worked on both the JLA/JSA: Virtue and Vice graphic novel and the early issues of Johns’ Green Lantern run. Additionally, Pacheco illustrated an arc of Superman/Batman with Jeph Loeb.

In 2009, Pacheco signed a new exclusive contract with Marvel, where his work included Age of Ultron, Captain America, and Ultimate Comics: Avengers. His final comics work was the cover for Marvel’s Damage Control #2 in September of this year. Upon its release, he announced that he was retiring due to being diagnosed with the neurodegenerative disease Amyotrophic Lateral Sclerosis.

Pacheco’s passing has been commemorated on social media from publishers and creators alike:

https://twitter.com/PaniniComicsEsp/status/1590398384091070464

https://twitter.com/thatpetewoods/status/1590379967799382017

https://twitter.com/philhester/status/1590391905199587328

https://twitter.com/jfornes74/status/1590398441846292480

https://twitter.com/CullyHamner/status/1590403166847533056

He will be sorely missed by fans and professionals.