Toby Fox's Undertale is intentionally vague with much of its narrative, which has allowed fans to come up with these fascinating theories.

Choosing to destroy or spare Asgore is a big decision in Undertale. Here's how to do both.

However, if you check the second floor of his shop, you'll find a group of several different color roses in a group, that mimic the group of souls Asgore collected from the humans in Undertale ...

Gaster is thought by Undertale fans to be the long-lost brother of resident skeleton sidekicks Papyrus and Sans. (Kotaku offers an in-depth explanation of this character's origins.) ...