Oden was the original user Yamata no Orochi fruit. When he was boiled into a soup, Orochi ate it and got the fruit in a similar way how O-Lin got Carmel's fruit.
Actually, him and Carmel may finally prove the theory that Blackbeard eats someone's heart when he steals their DF, which he presumably did with whitebeard. The theory would be that the DF ability resides in the physical heart and eating it steals the DF ability. Blackbeard either has more than one heart(his 'strange body') or it is the theory that Blackbeard has 2 brothers who hide in the darkness dimension of the Yami Yami no Mi, one of whom ate the Quake fruit by eating WBs heart. There are incidents like Jesus Burgess confronting Sabo and Luffy with a knife which don't make a lot of sense(he uses fists, not weapons) without this theory. And it would even explain how BB stole a DF in the first place from someone who had the ability. It's a better theory than the one where you hold a fruit next to them as they die, as at that rate, all pirates would steal DF abilities frequently. This way it is something more 'evil' which many would not lower themselves to do. There is still another method, searching the area for the nearby fruit which has it, but it would probably be less efficient. It may be possible that if the DF reincarnation cycle involves free will and an actual spirit or 'Devil' holding the ability, that holding a fruit up to the dead person as they die may not work, as it would if this was just like a natural phenomenon. That would make the theory make sense, BB would then simply be taking the ability by force even if the 'devil' holding it would normally choose to appear in a fruit far away from Blackbeard's reach.
My theory right now would be that Blackbeard might go after Kaido's DF next. Right now he has Quake Quake for destruction and Yami Yami to disable powers. Kaido's "Invincibility" along with Flight in dragon form would remove all of Blackbeard's weaknesses. He could probably even pick up his crew by holding the ship in the mouth of his dragon form and thus make the ship invincible and fly to next destination as they tell him where to go with log pose. Would be great for helping the crew escape a bad situation too.
Kaido may be invincible but he is not undefeatable, he has been captured before. Luffy and co will somehow defeat Kaido, possibly with the help of memory-less Big Mom who they convince into helping somehow. An unmarked small ship sails in with seeminly only civilians. Then suddenly all the BB pirates jump out to attack the defeated Kaido.BB and co get past the inspection of their ship by having Shiryuu turn all the elite fighters including Blackbeard Invisible as the insides of the ship are searched as they approach Wano. The Marines probably tried to execute Kaido with seastone or seawater before but it never worked because his base form is always half dragon, and seawater onlg suppresses DF abilities, it doesn't take away base qualities of the body.(Kaido presumably breathes underwater and/or can go entirely without oxygen due to his Ancient Dragon fruit) However, BB's Yami Yami no Mi turns out to be able to disable his dragon form. That, or BB thinks of a way to bypass the regeneration Kaido may have, which was too gruesome for anyone to think of, by eating his heart to steal the DF ability. Either way he steals the fruit then boasts to Big Mom who has gotten her memories back after seeing kaido die. " Now I've got all the strongest powers! The invincible Ancient Dragon fruit, the unstoppable Quake Quake Fruit, and the Darkness Darkness Fruit that can nullify any other power! Zehahaha! Nothing you can do now! You should all just bow down to me, the new Pirate King!"
Because Big Mom, Law, Luffy, and all of Kaido's forces would be after him, although he would have preferred to take Big Mom's fruit for one of his crew, after finding them too strong to quickly defeat, and seeing the giant Kaido fleet in position to soon blow up his crew's ship, he runs away with the Flight of the dragon form, picking the ship up in his mouth and carrying every BB pirate off. Since he became stranded from the rest of his fleet in order to sneak up on Kaido and killsteal, so he can't kill everyone right away. As BB just flies up and away into the sky after failing to kill everyone with tsunamis due to Big Mom, and announcing to the world that he is Pirate King now, he meets up with the other BB pirates in his fleet, and heads off for the final island to go for Raftel."It's too bad I won't get to see her face when she figures out we raided her island while she was gone and copied her Poneglyph! Zehahahaha! Good job on copying both those Poneglyphs and sneaking us around, Shiryuu! Now my Age has finally come!"
Then they will probably end up racing him to Raftel, probably with Big Mom making an alliance out of necessity. BB's biggest weakness has always been durability and no Logia will solve that like Kaido's invincibility can. Big Mom may end up being the only person able to finish him off due to her Soul Soul fruit, as he will be afraid if his invincible dragon body defeated and thus vulnerable to lifespan theft.
