Character: Jake the Dog

The other main character of Adventure Time is Jake. Jake is Finn's older adoptive brother. He is a magical dog, with a variety of special skills and powers. In magical dog years he's 28.

Jake is an funny character. While he can do things that are completely unlikable and seem unjustified, he does have good intentions most of the time.

While he tends to be a bit of a slacker and unmotivated by most things, he is deeply loyal to his bro. Despite this loyalty, there are times when he is extremely selfish or unfocused on what he's supposed to be doing, such as when he needs to rescue Finn from gnomes. 

Jake has an ability known as "Stretchy Powers" that allow him to transform into various objects. This isn't just limited to his full body, but it can also be specific parts of his body such as his arms, legs, or even head.

Jake acts as a "voice of reason" to Finn sometimes. I put that in quotes because there are sometimes where Jake's advice is truly terrible and unhelpful. Its often well meant and it does come from a place of caring, but due to his somewhat flawed morality it turns out to be bad.

I like the character of Jake acting as a foil to Finn's unquestioning heroics. Jake does do things that are highly questionable, such as grave robbing and bike theft, but he mostly has his heart in the right place of helping people. He's shown to be a good boyfriend to Lady and is loyal and supportive to his friends. He's likable  though seriously flawed morally. It works though, and that's another part that makes me enjoy this show.