I've just gotten a little bit of info about this release. Warhammer, The End Times is noted to contain new rules that change the way a game of Warhammer can be played. It is not a new edition.
Warhammer: Nagash - 2 hardback books in a slip case. €65
Book 1: 296 page fluff book detailing the return of Nagash and events that affect every Warhammer race.
Book 2: 96 page book containing rules for Nagash, new miniatures, the Lore of Undeath, Undead Legion, fighting underground and more apparently.
Nagash - no mention of him being a dual kit, rules are included in the box. €85(!!)
Grey Knights bundle.
The recent unofficial announcement of the return of Nagash has sparked much speculation over the direction GW are planning to take Fantasy in. There are rumors abound that the Fantasy timeline is progressing once more and Nagash is the herald of these changing times. To help fuel these fires we have a little bit of information regarding the upcoming Fantasy releases from Felweather over at Warseer. As always please take rumors with a pinch of salt, nothing is set in stone until we start to see more WD leaks.