Heroes stays and are summoned in the lobby of THEIR world. Han is an exception. For example let's talk about Townia.
Townia was destroyed and then the lobby was created. Let's say that the starting point in time is 10 years before the destruction of Townia. Each time a hero is summoned, they must have been alive at that specific time. Then heroes start climbing the tower and what they do the first time they conquer a new floor becomes history and can't be changed. Now let's pretend that at floor 20 we are 5 years before Townia's destruction. Now the only heroes that can be summoned are those that didn't die from year -10 to -5, considering the new history made by those climbing the tower.
So, had the master summoned a 5 star hero before this last mission, he would have been able to get Delphinis, but now she is dead because she died during the climbing of the towera and can't be summoned anymore. Last consideration, if Han died now and the mission was a failure, they would go back to this mission starting point and the history wouldn't be set, so Delphinis would be alive.
It's succeding missions for the first time that created history!
I don't get it, so the summoned heros come form actual reK places.
Next up the the tower are real historical events that happened in the past?
But then as you climb if you summon heros that's are in the historical event your are climbing. The a history changes?
So what is actually going on in those places where heros are getting summoned from? That whole world is destroyed?
Hans world was just a normal human world though