I used to love this manga, but it has seriously jumped the shark recently. God-like powers, killing people left and right, vampire plagues, it's more like a western superhero comic than anything else. And I have nothing against western comics, I read some of them too, but it's not what got me...
I'll be honest, that sword is just so dumb. I have way less interest in this fight now, because any solution they come up with to win is going to be just as BS as the sword itself.