It's a battle of religious (?) proportions as Inuyasha's letcherous monk battles the witty and secretive demon priest from the Slayers! Which monastary badboy would win?
Personally, I'd put my money on Xellos-sama. Sure, Miroku has his "wind tunnel" (or whatever the japanese name is), but I think Xellos has a few tricks up his sleve!
Xelloss is one of the most powerful demons in the Slayers world. The only ones more powerful than him are the four big demon guys, Shabranigdo, and the Lord of Nightmares. Miroku may have that wind tunnel, but he's still just a human. Xelloss has the power of phasing and if he dies, he just goes back to the Astral Plane. Not to mention Xelloss can phase and he can destroy an ARMY of dragons simply by pointing a finger. confused So it's really a no brainer.