The Watcher's Keep

Indestructible, Shroud
Demogorgon, Prince of Demons can't be played.
The Watcher's Keep enters the battlefield with
ten imprisonned counters on it.
{3}: Remove an imprisonned counter from The
Watcher's Keep.
{b}{b}{r}{r}: If there is no imprisonned counter on
The Watcher's Keep, sacrifice it. Then you may
put Demogorgon, Prince of Demons onto the
battlefield from your command zone.