Possible Spoilers up ahead
I've been thinking. Blackbeard supposedly doesn't do anything without a purpose. He joined Whitebeard to improve his chances of getting a hold of the Dark Dark Fruit. Then he killed Tatch to actually be able to eat it.
Those situations alone bring up a question right of the bat. Why does he want the Dark Dark Fruit? He did say he wanted it because it was the most powerful Logia in the world. But why does he want power? Why does he want to become the Pirate King? Does he believe that One Piece is a humongous treasure, or does he know of something we don't?
Moving on, we assume Whitebeard was at the New World when Teach abandoned the ship. But where did he go from there? Why did he leave the New World? Why didn't he recruit a crew there and moved on. Pirates from the New World have to be a whole lot stronger than pirates from other places, in general I mean. And being in the New World would certainly make it easier to reach Raftel. Was he looking for someone specific?
Moving on, we know Blackbeard gathered a prestigious crew, Laffite, Doc and Stronger, Jesus and Augur. He may have traveled out of the New World to get them, we do know Lafitte is from West Blue, so maybe Blackbeard left new World just to get these crew members. What makes them so special?
Either way, it seemed Blackbeard wanted to lay low for a bit, and decided to only show up once he had caught an infamous large bounty and buying his entry in the Shichibunkai. But something bugged me. Why did he rampaged on the Drum Kingdom? I initially thought he wanted to find a doctor there, given that it was know to have the best doctors in the world, but looking back on the picture it clearly showed 4 members appart from him, despite looking different (They were drawn quite a while, it is no surprise Oda changed his mind about the character's looks)
So Doc was already there. Then why? He was keeping a low profile, and certainly attacking one of the Kingdom that participates in the Reverie is not a good idea. So what were his reasons?
So yeah, that's what's been bugging me. We know Blackbeard wanted the Shichibunkai title to get into Impel Down and we know he wanted to get into Impel Down to recruit the baddest among the worse criminals, and he did that so he could challenge Whitebeard and get his powers, the strongest Paramecia in the world. But why did he do it? What are his true motives?
So, why Drum Kingdom, and what are his true ambitions?
As a side-note: There is a theory around the fandom called the Chimera Theory, based on a real life phenomenon. People think Blackbeard is actually 3 people in one (sounds less crazy if you are presented with all the facts), and each person can have one DF of each type. Thus Dark Dark Fruit, Logia. Quake Quake Fruit, Paramecia. If this was true, what would the strongest Zoan fruit be?