FAQ

Finn is the human boy and Jake is the dog. In every episode there is an intro that will remind you of this.

Finn is a human boy who was found by Jake's dad, Joshua, in the forest. His duty is to protect the Land of Ooo from evil such as the Lich. Jake is a magical dog who can stretch to any length, shape, or size. He got his stretching power by rolling in a magic puddle as a puppy. Jake's blood relatives consist of Joshua, his dad, Margaret, his mom, and Jermaine, his brother. All of his blood relatives are dogs as well, but none of them have stretching powers like Jake. Finn is also Jake's adopted brother. Jake's quest is the same as Finn's, being righteous and such, but Jake is more laid back and like's to goof around and mess with Finn.

In several episodes, there has been talk of a "Mushroom War", meaning the mushroom cloud of a nuclear missile has been seen by people living in the Land of Ooo. Marceline is a vampire that is 1,000+ years old, yet she was shown as a child in the ruins of a city when the Mushroom War had stopped. Ice King is also 1,000+ years old, as it has been shown that he was a human before the Mushroom War. If you pause at the beginning of the introduction, you can see a cassette and an old tv - both from the 80's. As well as this, there are nuclear bombs which haven't yet exploded. This probably means that the Great Mushroom War took place in the 80's. Therefore, Adventure time is probably around 1000+ years into the future