There is a future sephiroth and a present sephiroth. Present sephiroth is dead and in the northren crater. Future sephiroth wants to change shit， but he cant because of watchmen of fate， spirits that want to keep the events just like that， and they were probably even following future sephiroth to the past to stop him. Im sure ive seen this concept before in soul reaver， where monsters attack raziel when hes travellin around time and messing with it.
