Alucard (Hellsing Ultimate)

VS

Esdeath (Akame Ga Kill)

Reason: The two most badass and sadistic fighters in their factions. Esdeath's heartlessness and Teigu vs Alucard's immortality and vampiric abilities. Personally, I think Alucard would win without a doubt. He's the king of the vampires for a reason. He probably wouldn't even need Level 0 to beat her. Thinking about it now, it's kind of one sided due to Alucard's crazy regenerative abilities.