Castle of Dragon, known as Dragon Unit (ドラゴンユニット, Doragon Yunitto) in Japan, is a side-scrolling action game for the Nintendo Entertainment System in 1990. It is a port of an obscure arcade game of the same name, produced by Athena Co.; the gameplay and graphics were significantly modified to suit the abilities of the NES.
The Dragon Master, Darklarza, has been terrorizing the kingdom for numerous years. The king was forced into exile by this threat. He retreated, with the bravest knight in the kingdom.
This knight, named Geraden, must hold his fort. Darklarza stages an attack on the king's fortress, breaks in and manages to abduct the royal princess. Bravely facing such threats as the "grabbers" in the aptly named Molesty Forest, treacherous jumps, and fairies which may or may not give him super powers, Garaden must wildly swing his sword at any in his path. Does he have what it takes to defeat the Dragon Lord Master Darklarza?