The Mysterious Island Captain is Captain Nemo, a fictional character created by Jules Verne in his novel 'Twenty Thousand Leagues Under the Sea'. He is a mysterious and enigmatic figure who commands a submarine called the Nautilus. He is a brilliant scientist and inventor, and is driven by a desire to explore the depths of the ocean. He is also a passionate advocate for the oppressed and downtrodden, and uses his submarine to help those in need.