Cerebus is a story that started in 1977 and ended in 2004. It's about an anthropomorphic Aardvark who starts off into the realms of Might and Magic. It's a lot like Conan the Barbarian, and uses similar parody characters from the Conan mythology within it. Cerebus even wears a helmet, necklace and has a shield that resembles Conan's. There's also real people like Alan Moore, Chris Claremont and even parody characters from Marvel, DC, and Image Comics within the series. Most notably the "Roach" and his aliases.
Soon after the first volume was completed, which incorporated all of those previous elements. In the second volume, the story took a turn into real serious business and went straight into pure politics. Which is when the amazing background artist Gerhard joined Dave Sim. Gerhard did the backgrounds to each issue to lesson the blow to Dave Sim's already hectic deadline. And Gerhard would stay with Dave Sim until the end of the series.
The most amazing part about this series is the aging of the characters in real time. From the time it started, until the time it ended, the series was known for having the characters age so dramatically it wasn't even funny. By the end of the series, Cerebus himself looked so old he was literally ancient. And Dave Sim himself had said that the series would end with the death of Cerebus. Which it did on issue 300. Which marks this series as the longest reigning comic series by a single author/team in North America.
Cerebus as a whole is a great story. It's sometimes criticized as being sexiest, barbaric, hateful and even homophobic at times. But the story and the intentions behind it are purely genius, as well as the artwork itself. And, if not for this series, the creation of other series such as Usagi Yojimbo by Stan Sakai or even the Teenage Mutant Ninja Turtles by Peter Laird and Kevin Eastman would've never come to fruition, as said by the authors.
Currently, the series has come back for it's 40th anniversary. But this time it's with Cerebus deep in the caverns of Hell. It continues from the shocking and controversial conclusion with how the original series ended. With Cerebus literally being dragged into the depths of Hell by Satan himself. As he begs and pleads to God to save him from his fate. Here's the link to that series. Cerebus in Hell.
Swords of Cerebus