How does Benn Beckman fight?

According to Oda, Beckman has the highest IQ of all the characters introduced in the East Blue saga. Since he is a first mate to a Yonko, he presumably possesses a great deal of strength.

When the Red Hair Pirates arrived at Marineford to stop the war, Beckman was able to climb on to a Marine ship’s mast and sit on it, all the while pointing his flintlock at Kizaru, without the latter noticing. Admiral Kizaru chose not to fight him, even though he had just fought the First Commander of Whitebeard’s crew and Whitebeard himself. It should be noted that Kizaru did, however, continue his attack on Luffy when Beckman came down to join the rest of the crew.

Beckman also single-handedly defeated Higuma’s crew of mountain bandits, afterwards telling Higuma to bring a warship as backup if he wanted to fight them.

Beckman carries a flintlock rifle with him, but he has yet to fire it, instead using it as a club on Higuma’s men and as a threat against Kizaru.