Necropolis is a large series of rooms hidden under Treasure island. The entrance is very dark with very little light. Some Box's are placed around.
Tick-Tock and Undying don't act like the suits down here. They will actually chase you if they see or here you. Any other characters can just be avoided by standing still. The Puppet is only active on Night 6 if you go down here. The Puppet will have a counter on the bottom of the screen that counts down from 100. Once it reaches 0 The Puppet will kill you. To stop the Puppet you must find it. Once you find it it will disappear and the timer will reset. If a Phantom attacks you it will attract the attention of Tick-Tock and/or Undying.
Puppet's a.i. Is based off of Emily from Emily Wants to Play.