Mangetsu may seem like a typical happy-go-lucky protagonist, but that's a mask hiding the emptiness she feels every day of her life. She feels like she's just existing, and invisible to the world. Fighting in a magical battle royale has so far been the only bit of validation she has that she can be special in some way.
Then of course you find out why she feels empty and hoo boy, does it hurt. She was created by Magiaconatus itself to be a companion to Shingetsu and encourage her to win Granbelm. Once she discovers her true origins, Mangetsu is suddenly wiped from pretty much everyone but the Granbelm contestants' minds; her family no longer recognizes her; strangers don't see her; even most of her contacts disappear. She's able to put a positive spin on things, but it's heartbreaking to watch this cutie suddenly lose everything and learn her whole life was a lie.
Shingetsu's life has been one tragedy after another. First, her biological family is killed. Then, her childhood friend turns against her for being more powerful than she is. She spends a long time being alone in a country she's not all that familiar with, and reluctantly fights in a magical battle for a title she doesn't want. Her only salvation is the friend she makes along the way, Mangetsu...who turns out to be a doll created by Magiaconatus to be her friend after Shingetsu wished she had one as a child. Oh, and we can't forget that Magiaconatus is responsible in some shape or form for all of the tragedies Shingetsu faced in life, all in a twisted plan to mold her into the perfect successor to its power. Give the girl a break, will ya?
Poor Anna. She just wanted to be the best mage around and make her family proud. Instead, her family regularly remark how weak Anna is, adopt a different girl with better magical abilities, and even the one display of talent Anna showed during childhood was a lie created by her friend in an attempt to make her happy. Is it any wonder why Anna eventually snapped and became a raging psychopath?
Her death is also just painful. Just when things go her way once again, when she finally has Shingetsu at checkmate... she is defeated and killed by her friend.
Kuon's motivation for joining Granbelm is to find a way to wake up her sister from a magically-induced coma. Just that alone makes you feel bad for the kid. Then Suisho has to go in and make her question everything her sister ever did...
Mangetsu's death in Episode 12. It's so hard to watch Mangetsu go out the way she did. In the end, she defended her friend and fulfilled her purpose. Yet you still can't help but cry...
The previous episode's lead-up to the final battle is worse, because Mangetsu spends time with her friends on a camping trip, even her little sister, who, at this point, doesn't even remember her sister anymore. Then at the end of the night, Mangetsu uses her sprinkler to write a simple message to everyone: "bye-bye". Everyone besides Shingetsu forgets about Mangetsu.
The ending. Hoo boy. Shingetsu may have won against Suishou and fulfilled her wish to rid the world of magic, but at the cost of her Only Friend Mangetsu's Heroic Sacrifice, being unable to revive her former childhood friend Anna and Kuon, and lastly, being unable to die or interact with anyone due to her existence being unstable in the current timeline. Fortunately, she didn't mind though.
