Father Anderson from Hellsing versus Hidan from Naruto. I thought, Hey, they're both kind of immortal, so WTF? I don't know, I'm tempted to say Anderson because his holy blades would probably hurt Hidan.
I think Anderson would win this. Throwing aside the immortality of both he'd easily win. With it, it would depend on what it takes to kill Hidan in a battle like that. Either way, if it's Anderson after stabbing himself with Elena's Nail, then he showed that his thorns are capable of consuming immortals on the level of Alucard. And I doubt Hidan would have enough force to break out of it.