The main three of the story are completely unequal when it comes to development:
Hino writes such a complete and compelling story for one male character, and get fans on his side, only to have things go to h*** in a handbasket for him.
The other male character is left completely in shadow, yet is ultimately the one who makes *All* of the pivotal plot decisions. Readers don’t know about his personality during any of these decisions, though, and this leaves only his looks to make him a likeable character. This lack of development is not the yummy “Ohhh ♥ , who is that?” kind, but rather it comes off as a “Ohhh, he’s hot... Wait, what did he just do?! Who does he think he is?! @$%#!”
It is not ‘tragic,’ it is overdone.
Vampire Knight would be a tragedy if readers could identify with the leading lady, Yuuki, which was impossible from the very beginning. It is a fundamental part of the shojo genre to have a main female character that is likeable. Yuuki is just a dip from the beginning, and after the events/choices of chapters 40+ unfolded, fans dropped the manga. Calling Yuuki, the *Main Female Character* of the manga, whom you are supposed to be kindred to, "ruined," "unworthy," and "dirty."
Other minor characters have valiant attempts at background stories, but these are ultimately left undeveloped or quickly killed-off (literally, killed) before details can be explained.
Readers are left frustrated and unsatisfied.
Good manga gone wrong.
