Legend Series by Kara, SooJung Woo

Once upon a time, a selfish king summoned the monstrous Bulkirin into the real world. The monster killed half of all human beings, leaving the rest helpless as to what to do. That is, until one day when a hero appeared and defeated the Bulkirin with the legendary "Seven Blade Sword." But...what does all this have to do with eighth grader Eun-Gyo Sung?! First, she gets suspended from school for fighting. Then, she runs away from home... moreOnce upon a time, a selfish king summoned the monstrous Bulkirin into the real world. The monster killed half of all human beings, leaving the rest helpless as to what to do. That is, until one day when a hero appeared and defeated the Bulkirin with the legendary "Seven Blade Sword." But...what does all this have to do with eighth grader Eun-Gyo Sung?! First, she gets suspended from school for fighting. Then, she runs away from home. The last thing she needed was to be kidnapped - and whisked into the past by a mysterious stranger named No-Ah! less

With the help of Eun-Gyo and No-Ah, the "princess" Nak-Rang escapes her captors. But just when they think they're out of the woods, the high priest Ho-Dong stops them at the dried up Mother Lake. There, a battle ensues...and a miracle happens.

Even after learning No-Ah's true intentions, Eun-Gyo agrees to help him search for the Seven Blade Sword - as long as he promises to keep her safe. When the trio stumbles out of the lush forest into a barren desert, No-Ah suspects another blade of the sword is the cause. But before they have a chance to investigate, they are caught in the middle of a power struggle at the village temple... moreEven after learning No-Ah's true intentions, Eun-Gyo agrees to help him search for the Seven Blade Sword - as long as he promises to keep her safe. When the trio stumbles out of the lush forest into a barren desert, No-Ah suspects another blade of the sword is the cause. But before they have a chance to investigate, they are caught in the middle of a power struggle at the village temple. Rumors of the temple monks' magical flute sound promising, but what can No-Ah do when he's locked up in prison? less