Ok, lets be respectful now. Ryuma is obvioulsy stronger than Oldbeard. Primebeard is a different beast. I just don't see anyone defeating him. The man is basically Garp with a supreme weapon and a broken fruit.
For example, he could very well be the strongest Ryou user ever.
You could come up with anything since the only info we have are :
Wano = Country of Gold = everyone wants a piece of it
Ryuma single handedly defended it against EVERYONE.