in the spirit of the new era.
we have seen alot of devil fruits, and every fruit have its own special set of attacks.
crete and name an devil fruit attack, choose a alredy existing fruit or you can also create your own fruit but you have to explain the fruit first.
dont limit it only to devil fruits only be creative :-D
Door to hell- bomb
a good attack for blueno would be to have a room full of explosives and let them rain down on his foes
door to hell- fire
having a room in constant falmes on a remote location and send you foe to that place and trap him there
door to hell - water
drop a df user in the sea