When the moon covers the sun, I feel like I'm lonely.

-

Eclipse.

In front of the French window stood a gorgeous woman, Kim Yongsun, or known as Queen Solar, who was elegantly gowned and crowned with diamonds, her gaze fixated onto the majestic sky.

Eclipse is just that common, as it happens almost once a month in her land, but she didn't like it, though.

When the moon covers the sun, she will always finds herself alone, lonelier than how it should be.

She turned around, and found herself in an empty hall.

In the past, there will always be someone who stays by her side and get amazed by Mother Nature's miraculous beauty together; However, the 'someone' vanished, banished herself into the dark, isolating herself during every eclipse.

That 'someone', is Moon Byulyi, the most respected yet feared High Knight in the kingdom, who’s also the Queen's guardian, struggling on her own in a locked, dark room. Her magical powers were blasting inside her, pushing her close to her limit.

In the dark corner, sat a girl with her hair, suit and cloak all dark, blending perfectly into the black.

Suddenly, a flash of light shone out from her body, lighting up the whole room while frightening her at the same time.

However, the light extinguished in the next second – or you could say it was devoured by something.

She squeezed herself, bringing her head close to the knees, pulling her hair unconsciously, as if it could ease her from the suffer of forcing her powers back into her body.

Of course, it didn't help – and the pain became more torturing.

Blood.

She could taste her blood as a result of her biting her lower lip. However it made her to feel more determined – she won’t give up.

-

It's for Yong, Moon Byulyi.

You should never give up, never.

Despite all of those torments, you shall not give up.

But it's just...let that moon go, please...

-

The light flashed again. And again, it was devoured by Byulyi, back into the core of her body.

If the eclipse lasted longer, she would have worn out her strength, and will never be able to hold back her powers, leading her to a situation which is what she fears to happen the most.

As a descendant of the Moon family, Byulyi inherited magical powers granted by Artemis, the goddess of the moon. The powers will reach its peak during eclipse, allowing Byulyi who owns a dual soul to have the ability to turn into a dark knight, whose name is the "Monster".

Ever since she turned into Monster for the very last time, her kind soul which is her usual dominant, Moonstar(called after her real name), had never showed up again.

Hence, when an eclipse occurs, she'll lock herself in that particular room, to prevent Moonstar from taking over Monster. She’ll always have the desire to turn back into her bright side when the sun’s shining warm, and she still could deal with it so far, but when it comes to her power’s peak, she will have to fight her bright self badly.

She really didn't want to get back to Moonstar. She can’t, she thought.

Moonstar is kind and warm-hearted, she wouldn't be as strong and terrifying as the cruel and cold-blooded Monster.

Monster has to be there, to protect the Queen from any danger, especially from the traitors, just like the very last time.

Monster must be there, to protect the Queen, the kingdom and everything that is loved.

And that's why, even though it's tough and unbearable, she still insisted to be the horrifying Monster.

 For the Queen, for the kingdom; For their home, for her Yongsun.

-

“Moon, Moon, What kind of moon?

Moonstar that protects you.

Monster that hides on the other side of the moon, devouring light.

Moon, Moon, What kind of moon?

Moonstar that protects you.

When the moon covers the sun.”

“Cut it out!", said Yongsun while slapping Byulyi on her arm.

As usual, that didn't work. Lying on her back, Byulyi continued to repeat the lyrics she sang for almost ten times.

And finally stopped when got hit in the belly by a book.

“Ouch! Why are you complaining?! My singing is not bad either!"

“Doesn't the repetition annoy you?!"

As Byulyi got up, rubbing her stomach while staring at her in such an disgusted expression, Yongsun was about to snap:

She knew that Byulyi was talented in music and was overthinking the priest’s words, but even her herself was getting upset about it.

They're more than family, did Byulyi expect her to be NOT disappointed about ANYTHING?!

-

“Your highness, you and Moonstar are destined to be bonded together, as the Kim family rules the kingdom while the Moon family assists, but please remember: Her duality. if there's a Moonstar to protect you, there will be a Monster to devour you."

When the priest said this to Yongsun, Byulyi was just merely ten steps away. Even though he lowered his old, raspy voice, Byulyi still expected something from Yongsun's sudden change in face expression, something concerning herself, and it might cause some seriousness.

As the selected heiress of the throne, Yongsun has her own thoughts, and if she's not saying it, it might be something that Byulyi shouldn't know about.

As someone “more than family" to her, Byulyi will choose to be caring; but as her knight, Byulyi chose to obey, shouldn't it be like that?

Yongsun chose not to go to her palace after they left the cathedral, instead heading off to the pond in the Imperial City with a cold look on her face.

Byulyi was following behind her, until Yongsun sat down on a rock beside the calm water and she sat beside her, leaving her white suit in direct contact with the moist grass.

When Yongsun finally got out from her thoughts, and looked at Byulyi who was going to ask her something but not knowing how to phrase them.

She pondered about this girl who had grown up together with her, everything was much to her memories:

A dual soul is really rare in this world, not even the Moon family had this kind of experience before, even so, both sides are the Moon Byulyi who Yongsun knew well enough.

The only Moon Byulyi, known as Moonstar, a knight and a member of the Moon family, and also Kim Yongsun's guardian a.k.a “more than family".

Why does it matter if the Moonstar turned into the Monster?

Moon Byulyi has never hurted Kim Yongsun, and will never ever hurt Kim Yongsun.

This is one of Kim Yongsun's beliefs, which was held tight in her little trouble-free and anti-complexity personality.

So, she told Byulyi everything about it.

For all day long, Byulyi's mode went gloomy.

Surprisingly, she recovered on the next morning, playing and joking around Yongsun regardless of her identity as a princess, just like normal, as if nothing happened.

Yongsun had already been anxious about it, and this made it worse, until Byulyi sang in front of her this self-made song.

Her anxiety transformed into anger.

-

“Doesn't worrying about the same thing for so long annoys you too?"

Questioning back, Byulyi snatched the book and threw it straight into Yongsun's hold.

“...Of course it is! But what can I do?! It's something to do with you! How could you be so unbothered?!"

Seeing Yongsun's hair went messy because she got pissed off, Byulyi smiled, lying down with her hands pillowing her head, then had her eyes closed, just like how she's been before Yongsun hit her.

However, this time she didn't sing, but said in a tone that sounds like telling a fairy tale:

“Moon, moon, what kind of moon?"

Yongsun sighed, and when she was going to say something to her fellow knight, the surroundings went dark suddenly.

Eclipse.

“Moonstar that protects you."

Her arm was touched, leading her sight to Moon Byulyi who had sat up now, a smile on her face just like any other ordinary day, staring at Yongsun in her usual look.

“Monster that hides on the other side of the moon, devouring light."

Then Byulyi transformed - black suit, fierce eyes - into the dark knight. As if she devoured light, she looked dimmer than everything. Her gaze darkened, sharp and cold, as if she'll kill everyone, but she still had the same soft spot for Yongsun.

“Moon, moon, what kind of moon?"  She smiled again, and she wondered if her dark knight state gifted her evilness, her smile seemed dangerous. She opened her palm with a white sphere which suddenly appeared and shining on it, “Moonstar that protects you."

Ending up the final word, Byulyi aimed somewhere abruptly, and the sphere hit a short statue in the Imperial Garden, breaking it into pieces right in front of their eyes, threatening someone who hid behind the particular statue to flee.

Yongsun was alerted, and thus she shot a crystal-clear bird figure into the air with a gesture of her left arm.

——Splashhh!

The bird figure hit the e