Someone posted an edit here with Nasujuro being based on something that opposes the Asuras, the Devas. Among other things they can turn invisible and only humans with the "divine eye" can see them.
Zoro's going to fight invisible swordsmen for the rest of his life.
Nerona Imu ? Sound like the Apex Super Villain of DC.
Neron DC Summary
Neron is a character from DC Comics, specifically associated with the Superman series. He is a powerful demonic entity and a major antagonist in the DC universe. Here is a summary of Neron's background and role:
Neron is a demon lord who rules over Hell in the DC universe. He is depicted as a manipulative and cunning being who thrives on corrupting the souls of both heroes and villains. Neron often makes deals with individuals, offering them great power, wealth, or their deepest desires in exchange for their souls.
One of Neron's notable storylines involves him orchestrating a massive event called "Underworld Unleashed." In this storyline, Neron offers various villains enhanced powers and a chance to achieve their greatest ambitions in exchange for their souls. Many villains take up the offer, leading to chaos and conflict throughout the DC universe.