k this might be crazy but i was thinking if marco is a phoenix, could it be that dragon df is dragon, because everytime he appears, there's a storm, wind, and raining and in asian these are dragons things yo.(no proof so far)
and like how the heck did he managed to go to where luffy was, well obviously let just say if his df is mythical dragon, then he can fly...
and just ask urself a simple question, if he is so weak, how the heck can he even stands up against the WG.
just some crazy thinking yo, dont mind me^_^