Angel Diary, vol. 1
by Kara and Lee Yuh-Hee
Princess Dong-Young was originally a boy, but had to become a girl to accept a betrothal to the Emperor of the Underworld. Unable to accept her future with the Demon King, she realizes that her only choice is to run away. Her plan is to join the human world disguised as a schoolboy! Now all of the Gods from Heaven and Hell are searching high and low on the Earth trying to make sure that a wedding happens.
There's a great description of all 13 volumes in the series here.
My thanks to Robin Fosdick, the amazing librarian at the Corvallis-Benton County Public Library in Oregon for her amazing Teen GLBTQ graphic novels list, which is where I found out about this series.
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