Many fans consider Ezio Auditore to be the most skilled of all the Assassin's Creed franchise protagonists. It goes to show with all of his achievements, such as finding the true nature of the Pieces of Eden, halting the Templars' plans all around the continent, and forming the modern Assassin Order. His unique fighting style would certainly overpower Arno if they were to have head-to-head combat. However, Arno could make a case for this due to him becoming a Master Assassin by his mid-20s. Arno also favored his array of tools that were not present during Ezio's time. It is safe to say that on an "anything goes" combat, it could most likely go either way.