 When Ryu reaches Castle Rock fortress , he encounters the stranger whom he met after his trip to the laboratory , who reveals his name as Clancy . He tells Ryu about a project he and Foster have been working on called the " Biohazard plan " . Clancy says that he can no longer work with Foster . He said Foster was designing creatures called " bio @-@ noids " – transformed superhumans that are infused with " life energy " that flows from an interdimensional rift that appeared after the demon from the first Ninja Gaiden game was defeated . He explained that this rift appeared at the site of the Castle Rock ruins , in which Foster rebuilt in order to harness this power . Clancy reveals that it was a bio @-@ noid that killed Irene , and that Foster controls the bio @-@ noids ; he pleas to Ryu to stop Foster . After making his way into the fortress , he encounters Foster and the look @-@ alike . Foster vows to eliminate Ryu and use the life energy from the rift and Ryu 's secrets of the Dragon Clan to make him into an all @-@ powerful bio @-@ noid . Just as Foster and the look @-@ alike advance on Ryu , Irene appears , to the amazement of both Ryu and Foster , and is armed with a machine gun ; she was working with the army with regards to Foster 's plan . The look @-@ alike then transmutes into a bio @-@ noid , which Ryu defeats . 
