Joanna Heartburg is the main protagonist of OtherWorld. She is the presumed creator of the Otherworld. He is a very dedicated, easily irritable and emotionally driven individual. He's made a lot of mistakes, but has been trying his best to rectify them all and get better.

At the start of the series, Joanna is incredibly hot-headed and even violent at times. She deeply cares for her loved ones, but has a lot of trouble properly expressing her feelings. He's very bitter and avoids human contact as much as he can, only ever talking to his friends. Even then, he prefers to keep his interactions as brief as possible, unless he is with someone he considers incredibly close. As Act 1 progresses, she gets more and more unstable, displaying aggressive behavior more frequently.

With the help of his friends he eventually recovers. From Act 2 onwards, he becomes more brave and less impulsive. He still struggles with his emotions, but refuses to ever let himself spiral again out of the love he has for his friends. With time he turns into a more determined, clever and strong person. He is more open to interacting with strangers than before. His behavior changes for the better as well.

He tries his hardest to prevent his family from falling victim to danger, even resorting to being willing to nearly die for them. He has a tendency to make snide remarks towards people he is up against, especially Nycti. He is a very musically inclined person, developing his guitar playing and singing skills throughout the whole series, as he aspires to become a rockstar one day.