So BB will have to be a descendant or reincarnation of another ancient dude? Imu was directly responsible for all the oppression for the last millennium, seems like he carries the much heavier sin already.
Let’s see it then though, I like Blackbeard way more anyways. If he is FV, it has to be done right which I can’t see right now compared to Imu’s buildup.
My point of view is simple
4 people were marked by IMU
Vivi - is Related to princess of Alabasta of the time of ancient kingdom - Lily
Shirahoshi - is related to ancient weapon which once belonged to Ancient kingdom..
Luffy - Joyboy
All 3 above have past tied with ancient kingdom.
And, a simple logical deduction says BB has to be related to some ancient kingdom figure as well.
Now, considering BB has dream of "King of the world" and also rivals luffy and then one can deduce that BB ancestor was once "King of the world" before IMU took it and he once rivaled joyboy.