User blog comment:Vazelos3/In Marshall's shoes/@comment-4161592-20131014222831

Note: Im  trying to predict what's going on into Blackbeard's head right now.

Lets start with his true purpose: What he really wants to accomplish :He wants to be the Ultimate ruler.Currently he has obtained 2 devil fruits:Darkness, and Tremor, and now he's after mera mera no mi,so what i'm trying to say is that gura gura is very well effective in water and by that he wants to be the ruler of seas, next comes yami yami no mi or power of darkness, with this kind of abilty he wants to put (probably) the whole world in his terror and control it as he pleases, so the dark ruler of land, if he's also able to win the fire fruit maybe he thinks that he'll be the ruler of sky, even though for this matter it would be goro goro no mi that would suit perfectly.If by any chance he proves to be successful by achieving the last task chances are that nobody will be able to get in his way.

Why he wants to do it: By fulfilling this mission he will be the last man standing and at the same time the so called nearest man to find One Piece/ be Pirate King.

Another theory: The three devil fruits, two of which he already has now, belonged to his own nakama so his own crew mates, And all three of them were killed by none other than him. (Killed Thatch,together with his crew killed Whitebeard, pretty much killled and/or defeated Ace).Personally i'm guessing that now he'll be after Marco and Jozu's Devil Fruit.

The only downfall of Marchall D. Teach might be his newly recruited nakama, i can't help but wonder wether they'll betray him or not, after all, they were Level 6 criminals of Impel Down.