I know probably a lot of people have already been spoiled many times for Undertale already, but I want to warn you anyway, haha!
The more I think about it, the more hurt I feel about Asgore. Having to continue being king after his wife of... who knows how long, suddenly leaves, never to be heard from again, and the death of his kids. He did make a promise to take the souls of any human that found their way to the underground so that the monsters could have hope after the deaths of their 'future'. But you notice once you get to him, he is not keen on carrying out that promise at all, despite the fact Frisk is the final key to freeing monsters from the underground.
Anyway, I wanted to do something quick for you guys, so here you go. Sorry it wasn't happier. ^^;