Can you explain the concept of 'Marvel Knights' and how it impacted their graphic novel output?

Marvel Knights, spearheaded by Erik Larsen and Garth Ennis in the 1990s, represented a darker, grittier approach to Marvel storytelling. Their graphic novels, such as *Punisher: Born* and *Hellcat*, moved away from the traditional superhero formula, exploring morally ambiguous characters and violent, realistic scenarios, pushing the boundaries of what was considered acceptable in mainstream superhero comics.