Richter Strategy:
Death is one of Dracula's most loyal servants. He attacks with his scythe and summons smaller scythes that home in on you. He also has a phase where he summons a giant scythe that sweeps across the screen. The key is to stay mobile and dodge his attacks. The Cross sub-weapon is incredibly effective against Death, as it hits him multiple times and can interrupt his attacks. Use your Item Crash if you have enough hearts for a burst of damage. When he summons the giant scythe, stand on the edge of the screen and jump over it as it passes. This is a challenging fight, so be prepared to use your sub-weapons strategically and conserve hearts.
Maria Strategy:
Maria's speed and double jump are invaluable against Death. Her Doves can hit him consistently. The Dragon sub-weapon is very effective, especially when he's summoning smaller scythes, as it can clear them out. When he summons the giant scythe, Maria can easily double jump over it. Her Item Crash is devastating. Focus on continuous offense while maintaining evasive maneuvers. Don't get caught by his scythe attacks.