Writer and Story editor of ReBoot. His work can be seen in some of the episodes of ReBoot's third season, such as Between a Raccoon and a Hard Place, Web Riders on the Storm and Showdown.

Len Wein was born on June 12, 1948 in New York City. A renowned comic book writer and editor, he is best known for co-creating DC Comics' "Swamp Thing" and Marvel Comics' character 'Wolverine', and for helping revive the Marvel superhero team the "X-Men".

Wein's first professional comics story was "Eye of the Beholder" in DC's Teen Titans #18 (Dec. 1968), where with co-writer and fellow future-pro Marv Wolfman he introduced the male character Starfire who was eventually renamed Red Star. Late the following year, Wein was publishing anthological mystery stories for DC's The House of Secrets and Marvel's Tower of Shadows and Chamber of Darkness. He additionally began writing for DC's romance comic Secret Hearts and the company's toy-line tie-in Hot Wheels; Skywald Publications' horror-comics magazines Nightmare and Psycho and its short-lived Western comic books The Bravados and The Sundance Kid; and Gold Key's Mod Wheels, Boris Karloff Tales of Mystery, the toyline tie-in Microbots, and the TV-series tie-ins Star Trek and The Twilight Zone.

Working with DC Comics, Wein's first superhero work for Marvel was a one-off story in "Daredevil #71" in Dec 1970, co-written with staff writer/editor Roy Thomas. Wein later began scripting sporadic issues of such DC superhero titles as "Adventure Comics" (featuring Supergirl and Zatanna), The Flash, and Superman, while continuing to write anthological mysteries, along with well-received stories for the semi-anthological occult title The Phantom Stranger #14–26 (Aug. 1971 – Sept. 1973).

Wein and artist Bernie Wrightson created the horror character Swamp Thing in The House of Secrets #92 (July 1971). Over the next several decades, Swamp Thing would star in DC series and miniseries — including an initial 1972–76 series begun by Wein and Wrightson, and the mid-1980s Saga of the Swamp Thing, edited by Wein and featuring early work by writer Alan Moore — as well as two theatrical films, and a syndicated television series. He wrote a well-regarded run of Justice League of America (issues #100–118) with artist Dick Dillin. He co-created, with artist Carmine Infantino, and wrote the backup feature "The Human Target" in Action Comics, Detective Comics and The Brave and the Bold.

In the early 1970s, Len began writing regularly for Marvel Comics. He succeeded Roy Thomas as editor-in-chief of the color-comics line in 1974, staying a little over a year before handing the reins to Wolfman. Remaining at Marvel as a writer, Wein had lengthy runs on Marvel Team-Up, The Amazing Spider-Man, The Incredible Hulk, The Mighty Thor and Fantastic Four, as well as shorter runs on such titles as The Defenders and Brother Voodoo. In 1975, he and artist Dave Cockrum revived the Stan Lee / Jack Kirby mutant-superhero team the X-Men after a half-decade's hiatus, reformatting the membership. Among the characters the duo created were Nightcrawler, Storm, Colossus, and Thunderbird; Wein had additionally created Wolverine earlier, with artists John Romita Sr. and Herb Trimpe, in The Incredible Hulk. Wein plotted the next two X-Men stories with artist Cockrum. These issues were then scripted by Chris Claremont, who developed the series into one of Marvel's leading franchises.

At the end of the 1970s, following a dispute with Marvel management, Wein returned to DC as a writer and then eventually an editor. He scripted a long run of Batman and collaborated on Green Lantern with artists Dave Gibbons and Mark Farmer. He also dialogued the mini-series Legends over the plots of John Ostrander and the artwork of John Byrne and Karl Kesel. As editor, he worked on the first mini-series Camelot 3000, and such successful series as The New Teen Titans, Batman and the Outsiders, Crisis on Infinite Earths, All-Star Squadron, and Alan Moore and artist Dave Gibbons's acclaimed and highly influential Watchmen miniseries. Wein later wrote a Blue Beetle revival, scripted a revamped Wonder Woman over penciller George Pérez's plots, and created the superhero Gunfire with artist Steve Erwin.

Following his second stint at DC and a move to the West Coast, Len served as editor-in-chief of Disney Comics for three years in the early 1990s. After leaving Disney, Len began writing and story editing for such animated television series as X-Men, Batman, Spider-Man, Street Fighter, ExoSquad, Phantom 2040, Godzilla, Pocket Dragon Adventures, ReBoot and War Planets: Shadow Raiders. In 2001, he and Marv Wolfman wrote the screenplay "Gene Pool" for the production company Helkon, and later adapted it for a one-shot comic book for IDW Publishing. In September 2004, Len completed a script for a Swamp Thing feature for Silver Pictures at Warner Bros. Through 2005-07, Len appeared frequently as a panelist on the Los Angeles theatre version of the TV game show What's My Line, and in 2006, collaborated with writer Kurt Busiek and artist Kelley Jones on the four-issue miniseries Conan: The Book of Thoth for Dark Horse Comics. He has also scripted the comics series The Victorian for Penny-Farthing Press and has written comic-book stories for Bongo Comics' TV-series tie-ins The Simpsons and Futurama.

He passed away on September 10, 2017 at the age of 69.