Grendel is a long-running series of comic books originally created by American author Matt Wagner. First published in 1982 by Comico, Wagner later moved publication of the series to Dark Horse. Originally a noir comic in the style of European titles such as Diabolik, it has evolved into, in Wagner's words, a study of the nature of aggression.

Grendel was the masked identity of Hunter Rose, a successful author. As Grendel, he worked as an assassin before taking control of New York City's organized crime. He first appeared in October 1982 in the anthology Comico Primer, and was given his own series in 1983. This was quickly cancelled due to the publisher's financial troubles. Wagner owned the character, however, so he used the opportunity to re-tell the story of Hunter Rose in a far less conventional style in Grendel: Devil by the Deed, serialized as a backup story in Wagner's series Mage; this was subsequently collected as a 48-page one-shot.

There followed an ongoing series which lasted 40 issues. It was written by Wagner and drawn by a variety of artists, including the Pander Brothers, Bernie Mireault, Tim Sale, John K. Snyder III and others. It began with a story set in the near future, with Christine Spar, Hunter's posthumous biographer, assuming the identity of Grendel to pursue a mission of revenge. The identity passed briefly, and tragically, to her deluded boyfriend Brian Li Sung. After a brief return to stories of Hunter Rose (actually two in-universe fictional novels written by Captain Wiggins, a supporting character from the Christine Spar arc), Wagner then spun the series further into the future, with the Grendel identity affecting a variety of people. The name Grendel took on several meanings as the stories portrayed a dystopian future. Grendel became a synonym for The Devil with the title held by the emperor of the world (Grendel-Khan) and members of a warrior society identical to samurai.

The publishing rights languished for several years after Comico's bankruptcy, but Grendel resurfaced at Dark Horse Comics with the ten-part series Grendel: War Child, written by Wagner. Dark Horse subsequently launched Grendel Tales, stories set in the world established by Wagner, created by other writers and artists, including Darko Macan and Edvin Biuković. The main story has also continued in novel form, written by Greg Rucka.

In the years since the publishing of War Child, Wagner has occasionally written short stories featuring Hunter Rose. In 2007, he launched an eight-issue miniseries, Behold the Devil, which reveals a secret of the character. In 2019, Wagner released Devil's Odyssey, returning to the dystopian future of Grendel-Prime.

Comico Primer #2 (Oct. 1982) contained the first Grendel story, introducing debonair master-criminal Hunter Rose and his nemesis, Argent the wolf. Grendel soon got his own black-and-white title, published by Comico, which lasted three issues. It ended prematurely, mid-story, because of Comico's financial issues. Wagner considers these stories a "rough draft". These issues, along with the aforementioned Grendel story from Comico Primer #2, were collected for the first time ever in the Grendel Archives collection in 2007, just in time for the 25th anniversary of the publication of the first Grendel story. The collection included an introduction by Wagner explaining the situation which led to the creation of Grendel, and dismissing rumors that he was unhappy to have the early work available.

As a backup story in his other series, Mage (1984–1986), appearing from issues #6 to 14, Wagner reworked and retold Hunter Rose's story in its entirety. It was collected by Comico in 1986. A new edition, recolored by Bernie Mireault, was published by Dark Horse in 1993. In 2007, it was released in hardcover colored only in black, white, and red. In 2023, a "Master's Edition" was released by Dark Horse Comics, expanding the story from 37 pages to 120.

The story begins with an extraordinarily gifted boy named Eddie. Because victory in his endeavors comes so easily, it all seems meaningless. In despair, he throws a world-championship fencing match and becomes romantically involved with Jocasta Rose, a trainer twice his age. When Jocasta dies, Eddie leaves behind his life and takes on two new identities: Hunter Rose, successful novelist and socialite, and Grendel, elegant costumed assassin and later crime boss. Grendel is hunted relentlessly by Argent, a several hundred year old Native American man-wolf cursed with a thirst for violence. Argent works with the police in an effort to turn his curse to good.