Sleeper's Tomb

[Toiletzombie]

Hello,

I am not sure if I quite understand how this zone works. Once you wake up papa dragon a bunch of the named bosses disappear from inside the zone right? Looking at the wiki there is no known loot, I am assuming because he is neigh impossible to beat, level 99 and what not. So what's the point? Does he have to be woken up to unlock new velious content? Seems kind of shitty that all those item's are unobtainable now. (Sceptre of Destruction, how many are on blue anyways?)