Knights in the Nightmare

Dude, Matador is SO HARD if you're not prepared long before you get to him. Nocturne is just crazy all together but yeah Matador is definitely challenging.

edit: On topic, I tried Riveira but I couldn't get into it. One, because there was a creepy fucking loli bath scene and two because the perfectionist in me wouldn't let me progress without making sure I did each level perfectly and something almost always went wrong at some point.

If you have the right Magatama then you're fine. I can't beat freaking Lucifer on Maniac. Which is why I'm not playing over Maniac + Evil side ever again. That shat is hard.