Spawn

Spawn is the titular hero of the long-running comic book series of the same name as well as the star of several cartoons, videogames and a live-action movie based around these stories - originally human Spawn was cursed into the life of a Hellspawn (akin to a revenant) and became a costumed warrior fighting against the forces of Hell and Heaven in order to protect the human world from the apocalyptic wars they were planning - one of his most famous archenemies is the Violator and the Spawn series is reputed to have helped in popularise the antihero as a main character in comic-books since the comics came out in a period of time when darker heroes started to emerge and gained much more publicity in comic books.