User blog comment:Kogath/Monster Hunter: World Discussion/@comment-24734669-20181019144453/@comment-15446856-20181019154916

It has a 25 min time limit, does more damage with its magmacore explosions, Nergigante is normal but must be repelled this time, and it charges up energy much faster in the second phase.

So its pretty much the same but made harder via other means.