Dr Blaise Gauss/Abilities and Powers

Swordmanship
Due to his devil fruit abilty Gauss has no need to use a sword but during several of the attempts to capture him he has been seen using a pair of Kukri knives to defend himself. He did so with great skill slashing at his enemies causing them to faint due to lack of blood but not killing them. He also appears to be able to use these knives as throwing weapons with great accuracy and skill. He also uses his devil fruit abilty to mutiply the knives while in flight and take down multiple targets.

Marksmanship
Gauss appears not to use firearms in combat so it is unlikely he has any marksmanship based skills.

Hand to Hand Combat
Gauss appears to be an expert in mutiple martial arts. This may be due to his ability to multiply himself. He has in the past sent duplicates to various locations to study different subjects such as medicine, engineering and other scientific based subjects. While there is no proof he might have done the same for martial arts the fact he such a wanted man and the way he uses his abilty makes this scenario the most likely.

Physical Strength
Gauss for most of his life was not a fighter and consequently before he consumed the the Namba Namba No Mi he had lower than average strength due to spending most of his life in the lab and the library. However now he has potentially unlimited strength.He has in the past smashed his way through stone walls with nothing but his bare hands and has even ripped the masts off several boats and swung them like clubs.

Agility
Gauss has always been fast due to his childhood however due to the Namba Namba No Mi he has unlimited speed. He can run faster than the eye can see and dodge any attack. He has to be careful when using his speed due to the other forces on his body such as friction. He can counter these forces with his ability but only by concentrating otherwise the forces will rip him apart.

Endurance
Gauss ability allows him to take much more damage than the average man. He can harden his skin and cause most physical attacks to bounce off him. This combined with his abiilty to speed up his healing processes means he is potentially unstoppable in battle. However like most of his abilities if Gauss loses his concentration his endurance will falter and he will become no tougher than the average man.

Weapons
Gauss's weapons of choice are Kukri knives. They don't appear to of any special manafacture but it is possible that due to his devil fruit ability he can strengthen weapons to the point he doesn't need anything special. For example he could increase the weapons toughness and sharpness so he could cut through anything without them breaking.

Namba Namba No Mi
A Paramecia type fruit which gives the user the ability to manipulate numbers and quantity. Since the world is made up of numbers it could used in many different ways. The user can create clones of themselves, create copies of objects, manipulate the atomic structure of various substances and many other abilities.

Haki
It is unknown whether or not Gauss has Haki based abilities but it is thought unlikely as his fruit allows him to do so many things that he could counter most abilities or attacks used against him. For example he once was able to counter an attack from Akainu's Magu Magu No Mi by instantly lowering the temperature of his attack and causing it solidify into rock. However nothing can be taken at face value with Gauss and he may just have never shown his Haki.