The Underworld (in Japanese: 魔界 Ma-Kai; the Fiend Realm) is one of the areas of Ninja Gaiden 2/Sigma 2 as well as Ninja Gaiden: Dragon Sword. This twisted, hellish netherworld is also the place where the [[w:c:villains:Fiends (Ninja Gaiden)|Fiends| live as well as where the Greater Fiends are sent to when killed.