In Mega Man X6 , Zero is not initially present in the game since he went missing in the end of Mega Man X5 during a fight against Sigma .
Zero becomes an optional character depending on how the story develops throughout the game .
In Mega Man X6 , Zero is not initially present in the game since he went missing in the end of Mega Man X5 during a fight against Sigma , and he becomes an optional character depending on how the story develops throughout the game .