User blog comment:Bunnyllove/Have Natsu and Zeref meet before?/@comment-24066070-20131111101402/@comment-4829046-20131111123335

I never said he needed to get hit by it to memorize it. And even if he doesn't launch it from his own limbs(wait what? O_o) the death magic will probably be harmful to him. Also this little weakness(ass-pull) is still there -

"this residing in the time required to memorize others' techniques: if those were to be performed too swiftly, Rufus wouldn't manage to keep up and properly get hold of them"

So if Zeref suddenly did his Death Sphere, Rufus has no chance.

And the "nothing will" is pretty much going to be blown away in the final battle.

True enough it will be unexpected. But if it does happen, I now know who I shall congratulate ^_^