Muramasa Sengo was a legendary swordsmith, alive during the Sengoku period of Japanese history. Chances are that if you have played video games for long enough, you have come across his name. He and/or his swords have made appearances in numerous video game titles, including mainstays such as Ninja Gaiden, Final Fantasy, and Castlevania.
Unfortunately, most of these titles have evoked the Muramasa name lightly. Sure, Muramasa was a master swordsmith, and games typically recognize him for this, just as Final Fantasy III rewards the Muramasa blade as the ultimate weapon for the ninja class, but that's only half of the legend.