As the recent events in the manga has shown how superior blackbeard have become,
many questions may come up on who in the One Piece world will be able to defeat him?!
Well, I just think that I can answer that question for you all!!! ^^,
If you remember from before when the Straw Hats encountered with Gecko Moria at Thriller Bark,
Gecko Moria stole their shadows so they werent able to stay in the sun or be hit by any sunlight
after that. And as you all now and heard of, Gecko Moria is now present on Marineford
where Blackbeard is also. So I think that if Gecko Moria would join the fight against Blackbeard,
and somehow manage to steal Blackbeards shadow, Blackbeard would be defeated even if he didnt
die. And would in either way die as soon the sunlight would hit him.
So thats my thought on how blackbeard can be defeated or killed.
Any comments you would like to add to this, feel free to do so.