Siege of the "Monster Association" by the "Heroes Association", you're a hero and have already gone down to its base which is under the ground, and you have gone through several floors lower and lower and it already looks like a dungeon. Now, you're on one of the lower floors and you've been stopped by a tremor, you were thinking about the cause until... "Are you really that concerned with the way other heroes are killed?" You hear suddenly, right behind you.