Thanks, I appreciate your feedback! Marceline has to look a bit sinister, since she is the vampire queen. The Arabic is part of my watermark and it carries an Islamic meaning. I know some Arabic, but there is still much to learn.
You mean my watermark? The calligraphy carries a religious meaning rather than a cultural one. "Bismillah ir-Rahman ir-Rahim" or in English "In the Name of God, the Compassionate, the Merciful", which is the opening verse of the Qur'an. Although Arabs are a minority amongst Muslims, Arabic, the original language of the Qur'an is used universally by Muslims of any cultural background.
I am not a big expert, so naturally I assumed someone in the Middle East drew this pic. Which I though was cool, because it would mean that Adventure Time has fans there, too. I know for a fact that the series was translated into Arabic.