San Juan Wolf was a member of the BlackBeard pirates in "One Piece". He was the largest character so far in the world of "One Piece" and known as the Colossal Battleship. He is originally one of the legendary criminals that was given a life sentence in level 6 of impel down until he was freed by Blackbeard.
He is known to be powerful in "One Piece" as he was contained in the level 6 of Impel Down. Level 6 of Impel down is known as the Eternal Hell. This is where the prisoners who are insanely powerful and have cause crimes so atrocious whose existences have become a major threat to the World Government. Prisoners that is on Eternal Hell would be given a life sentence or death penalty that basically erased them from history.
His abilities and skills up to date is unknown as it was not yet seen in both Manga and Anime of "One Piece". A testament to his power is being a giant. As a giant, he shares their attributes and immense strength but still not known to what degree his power is. Another testament to his power is the fact that he is a prisoner of level 6. He was one of the people who survived the battle royal inside Eternal Hell or Level 6 of Impel, making him one of the strongest prisoners.
One of the things he did in "One Piece" that could be related to his power is being undetected when Blackbeard pirates invade Marineford during the war of marines vs Whitebeard pirates. He was the largest giant so far in "One Piece" but no one was able to detect him.
Right now, everyone is hoping in "One Piece" to see the power and abilities of San Juan Wolf. He will surely be a powerful opponents for the Straw Hat Pirates.