Gotta say, this is one of my favourite swords, and at +50, it's pretty good at destroying mobs. Lightning Slash VII, Empty Sky Slash V and Blue Fang Blade V really help those monsters find their way to hell in a thousand pieces. Could do with getting some Ougi for this bad boy, but as if I'm that lucky rolling Nyan.
The only problem with using Nyoibou is that when you equip it; your max health goes up so it looks like you've taken more damage. Then you heal up, switch back and your max health drops again. It's the best staff I have at the moment though, which isn't saying much, but once I get to Kyoto I can get better ones.