I've got to give some credit to a good friend, KrAzY K for discussing the idea of it with me and that elaboration brought us to this new theory. It is strange why Blackbeard would cover Whitebeard like that though, almost like Oda was trying to hide something that was so gory to be shown. Many do believe it is a characteristic of Blackbeard's Devil Fruit to be able to negate, neutralize, and even absorb a devil fruit's powers. But, if this was the case, he could have in a sense just stolen Ace's devil fruits powers right there. Many assume he could only withstand two devil fruits and wanted the other to be Whitebeard's and nothing less and his plan revolved around the capture and sending Ace to the Marines in which he could then make his statement in front of the world of resigning as a warlord and having two devil fruit powers. Although, now when I think about it, why did Blackbeard send Jesus after Ace's Devil Fruit in Dressrosa now when he could have just taken it before. At first, it seemed like Blackbeard had no intention of stealing of Ace's Devil Fruit, but now he wants it again. Also, Blackbeard didn't want to steal his Devil Fruit and instead wanted him to join his crew. Once he died, he wanted the fruit again for some reason. It's possible Blackbeard could have potentially eaten the part of the body that keeps people alive and even holds their will, spirit, and even devil fruit powers: the heart. Also, one of the strangest unnoticed lines by Blackbeard was to "make a honeycomb" out of Whitebeard. We all know a honeycomb is something kind of like a fence that has holes in it and past it is the treasure, the honey (in this case the heart). Blackbeard ordered them to make holes in this body that would not kill but would give him the access to Whitebeard's heart. Also, he covered his body so now one would learn his secret maneuver. Blackbeard is as gory and monstrous to do such a thing anyways. I'm convinced the will, the spirit, the devil fruit are all connected in one body part, the heart (as cliche as it sounds). Oda would not unnecessarily make this much emphasis on attacking his heart. He also had a giant hole and void very close this heart. All the major attacks were near his heart. After the cloth was removed and Blackbeard came out, one Marine said it doesn't seem like there's any difference to Whitebeard. The reason he said this as faith would have it, there happened to already be large openings to the heart. Also, with the excessive bleeding no one could notice the missing heart anyways. Also, Blackbeard's reasoning for getting everyone to gang up and attack him even more brutally was to paralyze him and make sure he's too injured to move too. If Blackbeard did it then, Whitebeard would just have killed him right there under that cloth so Blackbeard waited for that moment when hes too tired and injured and basically paralyzed in order to capitalize. Also, Blackbeard did not want to make the risk of costing his life by doing it early. I believe this part could be related to Blackbeard's Yami Yami no Mi in which he has the ability to keep the person alive and make them suffer a little longer by using the darkness to keep the devil trapped. Blackbeard did say its a unique power of this devil fruit and then ended up with both powers. He could have trapped the devil using darkness to keep it within the heart and then simply eaten the heart to get the power. Just like a devil fruit, it does not have too be attached to a tree or vine, and be eaten from the root to get its powers. A Devil Fruit can be eaten with no stem on it as the devil is in it. Just like that, if the devil is trapped in the heart when the user dies and the heart could simply be ripped out and eaten like a fruit with no attachment to the original roots (the body). It was too gory to be shown and so it was covered with a cloth and also to raise suspicion of what Blackbeard mysteriously did, and also to make Blackbeard's secret technique hidden from everyone in the One Piece world. Also, I highly advice watching the fight between Ace and Blackbeard: The key parts are from around 11:20 to 14:15. There are extremely interesting things in this fight like the fact Ace's chest (specifically his heart) is the part of the body being pulled straight forwards towards the darkness of Blackbeard's hand. Ace's body is not being pulled, but we see that his heart makes a strong heart beat and then instantly the heart/chest is flying towards the darkness. Another important fight to watch is Luffy vs. Blackbeard: The key parts are from around 1:20 to 3:05. There are very important moments during this fight like the part when Luffy's chest gets pulled towards Blackbeard's hand. Blackbeard used Kurouzu in order to do this move. The video also shows important lines Blackbeard said regarding his Yami Yami no Mi like the fact devil fruit users fighting him become completely incapable of using their powers. Kurouzu Extending one arm towards his opponent, Blackbeard activates the gravity power of his darkness to pull them into his grasp. Blackbeard can then attack them with his massive strength. This move is particularly useful when used in conjunction with the fruit's power-nullifying abilities, since the target could easily avoid it by fighting at a distance from Blackbeard, as Ace attempted. However, this technique has also proven to be a great weakness, as most opponents he draws near him have attacked him while at close range, such as Ace launching two fiery spears into Blackbeard's chest, or Whitebeard slamming his bisento into Blackbeard's shoulder. This was first seen being used on Ace in order to grab him. The darkness attracts the devil like a magnet and brings them towards the darkness. The devil lives inside the heart and this is attracted to the darkness and brings the whole body with it. Devils are known to live with evil and within darkness, and so it is fitting for it to be attracted to this darkness. Also, in many ways, the heart looks very similar to Devil Fruits: View attachment 7931 They both have a similar structure, lines, swirls/veins, and even stem-like parts. They are both the essential part that holds life (heart holds the will and spirit, the devil fruit holds the devil). View attachment 7929 Also an interesting point to recognize is that both the anime and manga shows how the devil fruit process works in which once the devil fruit is consumed, we see the man gains a power-up, but the fruit is gone and as we all know, once a devil fruit is bitten, the fruit loses its devil powers and turns into a normal fruit. In a similar manner, once the devil fruit is consumed, the devil needs a place to stay now and that place is the heart because of how similar it is to fruit and directly affects life and the whole body. For the powers to reach the whole body, the devil needs to effect both the user's life and also their whole body which is why it chooses the heart. Also, in the last part of the cycle (the death of the user), we see that the "spirit" or devil of the devil fruit then leaves the body, in which it exits from the heart. The Importance of the Yami Yami no Mi Years ago, Blackbeard read about the Yami Yami no Mi, and hunted for it. He joined the Whitebeard Pirates as he believed his chances of encountering the fruit is best while there. Blackbeard had evil intentions from the start, but acted good like Shanks said before with the sole purpose of trying to get this unique devil fruit. From what we know, this is the only devil fruit with such an ability, and so Blackbeard orchestrated a plan that would give him the biggest chance in receiving the fruit and that was to join the Whitebeard Pirates. Once, he found out Thatch found the Yami Yami no Mi, he killed him and fled with the fruit. This fruit must be very important if one is to go this far and mess with an emperor whose crew ("family") is his most prized possession, but to Blackbeard he needed to do this. The fruit is unique in that it has the capability of directly effecting the devil of a devil fruit because of its darkness. Devils are known to be linked and related to darkness and so this makes a lot of sense. As we have seen before with Blackbeard fighting Ace and Blackbeard fighting Luffy, we see their chests flying towards him where Blackbeard harnesses the darkness to his hand and does his move. Their devils live in the users' hearts and so it is pulled towards the darkness. View attachment 7930 Near the start of the series, Morgan described Devil Fruits. As ironic as it may be, the centerpiece of this cross of Devil Fruits is none other than the Yami Yami no Mi or the Bara Bara no Mi. Right underneath it, we see the Gomu Gomu no Mi (could potentially be involved in a larger schemed theory), but for now, I'll just talk about the Yami Yami no Mi. As we see, its the possible centerpiece because of how it impacts nearly ever devil fruit because every devil fruit has a devil within it. The Yami Yami no Mi, in many aspects could literally overpower any devil fruit because it produces darkness that all devils within the devil fruit users possess. It is a power that can control and even make any devil fruit user defenseless like Blackbeard said many times. It could be seen as the most powerful devil fruit because of its impact on devil fruits and its users because the devil resides in the users' hearts. This means Blackbeard literally did eat Whitebeard's heart and not just figuratively. Its symbolic of just how evil Blackbeard really is and his willingness to do anything to get power. We've seen his plan to become Emperor, but this extends his evil ambitions further on how and what he did to get there. It is excellent irony and symbolism on Oda's part. In conclusion, this explains how Blackbeard had gotten Whitebeard's devil fruit.