where do monsters go when they die I mean is there a place for different class monsters like boss monsters and monsters with low attacks?
Hmm, I don't think there would be any difference depending on what class a monster is. Obviously we don't get much information from the game- but the monsters generally believe that spreading the dust of a monster onto their favourite thing (the game specifies thing instead of item, hmm) will allow them to live on through that. Of course it's just a belief and no monster has come back through anything-
Except Flowey.
Considering that Flowey exists with the memories and personality of Asriel, this is true. All they need is a little determination pff.
But there is only 1 Flowey, while Asriel's dust should have logically spread over a larger area. So it seems like even a small amount of their dust can hold everything about them. Or perhaps the determination drew everything about Asriel into Flowey?
Anyway the point is that the dust seems to only spawn one version of the character- it can't have more than one, there are a lot of flowers in the lab, and the entries say how Alphys eventually resorted to injecting everything with Determination. But there is still only 1 Flowey.
To answer the question directly: No, they don't go anywhere. Their dust is waiting for someone with the abilities and knowledge to bring the lost monsters back.
Obviously the monsters have no idea this is possible. So the dust sits on their favourite thing.
I think if Alphys found out who Flowey was, she would research it to see if it could be done for other fallen monsters. The most important thing is that the dust can't just form back into the monster it used to be- so it would need a container.. but then there's the risk of... well, Flowey.
Flowey has a save location, and creating another monster like him would risk this new one having a save location, or worse- a file.
Anyway.
Ruining my first point- maybe this is only possible because Asriel is/was/technically a boss monster. Maybe it wouldn't work for normal or lesser monsters.
It really makes me think about the pet rock that Papyrus seems very intent on feeding, though. Maybe he knows something we don't? (OF COURSE HE DOES)
That's all the information I think I have pff.
