300 isn't a DC comic. It has its own independent creation and doesn't fall under the DC Comics universe. The story and characters are distinct from DC's offerings.
To understand Mazikeen, you need to pay attention to her character traits, motivations, and her interactions with other characters. Her backstory and development throughout the comic series also provide crucial insights.
Vampirella wasn't a DC comic. She has her own independent comic series and background separate from DC's universe. DC has its own array of characters and storylines that don't include Vampirella.