Thread:Birdofterror/@comment-27581425-20170622131653/@comment-32352928-20170622143439

So you just want a rundown of possible motivations? I think I can work with that. Though it's worth stating ahead of time that no human on Earth is aware of the monsters' continued existence, except perhaps the humans who saw Asriel. Whatever motivations for humans falling into the underground are more or less headcanon. The only canon reason we have is Chara, who explored Ebott in an attempt to commit suicide, as explained by Asriel.

Patience could fall down after analyzing the legends and realizing that Monsters might exist underground, then climbing the mountain to find out.

Bravery might recall old stories about the war and be fascinated with the concept of finding humanity's long lost enemy.

Integrity might seek out monsterkind to figure out why the war ever started, and to find the truth of who the true aggressors were.

Perseverance might start realize one day that if monsters DO exist, then they could be a threat to humankind, and so they would check Ebott to make sure, and then fall.

Kindness have no actual motivation to climb Ebott at all. I cant really imagine why.

Justice might climb the mountain to settle the score between humanity and monsterkind once and for all.

Determination, Chara, Frisk, potentially both of them jumped into the Underground simply to commit suicide. At least Chara intended to, at first, but found a better use for their life through Asriel, to start a second monster/human war.