Design a promotional flyer inspired by the MMORPG Mu Online. The flyer must have

Design a promotional flyer inspired by the MMORPG Mu Online. The flyer must have a medieval-fantasy style, with a dark background and bright elements that highlight the action and magic of the game. Includes images of iconic characters, like a Dark Knight in heavy armor and a Dark Wizard casting spells. The text should highlight the name 'Mu Online' in an attractive gothic font, along with phrases like 'Join the battle' and 'Explore magical worlds'. Make sure the design is eye-catching and conveys the epic and mystical essence of the game, with well-integrated details and a visual balance that captures the attention of players