Advent Children (MAJOR SPOILERS)

[Midgar Mist]

I haven't read those novellas so I missed out on those tidbits of information. Maybe I should try reading them if I can find them that is.

Also I knew about the shapeshifting thing in the main game, it just kind of threw me off when the remnant (temporarily forgotten his name) Said "my reunion" just before he became Sephiroth. Also the gang was going on about how he was a "larval form of Sephiroth" which seems to be suggesting something other than the usual shapeshifting that goes on.