Re: Luffy and black beard
.. Yami-Yami no mi works like Kairoseki only to deactivate the Devil's Fruit ability. The moment Luffy gets touched by Teach. Teach can hit Luffy, that where rubber gets deactivated. It will bring more pain to Luffy. When it comes to physical attacks Luffy has no problem with that, because he's a rubber-man, but Luffy never experienced pain while his ability being deactivated.
Sharp weapons like swords are what Luffy have had experienced so far. He never been bruised by a hit. If Busoshoku Haki can protect Luffy from physical attacks instead of his rubber ability, then this is the only solution.
How far do we know about Teach? He punches. His punches are the only thing we saw so far. I'm 100% sure Teach have only two forms of Haki. If he has Haoshoku Haki, more or less it won't make any difference since it only mentally knocks down enemy.
If Teach grabbed Luffy and used Busoshoku Haki, well, it's only who has a higher level of Busoshoku Haki.
Has Teach ever gave it a thought about what Whitebeard said before he died?
"It's not you the man Roger is waiting for at the very least, Teach."
Only who has the will to move on is the winner. This is going to be a great battle between two men of the D family. The one who has the will. Teach shouldn't be misunderstood. I'm sure there is a back story about him for why being interested in One Piece that much. There are others too like Kidd and Law, but this is a guy from D family, and those D family are no ordinary people.