This character is known as v1 Usopp, story-mode Usopp, or just story Usopp.
Be careful when evolving him for the first time. His final form, Sogeking, is considered inferior to Usopp Usopp Golden Pound, and so is Usopp Tabasco Star. You should evolve Usopp to his Golden Pound version ASAP. After you get one Golden Pound, other Usopp's can be either evolved to Golden Pound as well (for raising skill levels or starting one with different sockets), or just used as sockets for your favorite Usopp (which is probably the Golden Pound anyway).