Personality:

"The Witch of Miracles who has lived a thousand years.
It is said that she lives in a world where concepts like fate and possibility can be visualized.
She can give birth to all kinds of miracles with her immense power
but, in compensation for that, her heart ended up breaking a bit..."

And no one would want to wear the shards of a broken heart on their sleeves. Perhaps it is the reason why Bernkastel is someone who's so difficult to read. In the presence of others, her usual expression is composed, almost blank, revealing none of her feelings ( if any ) even in the most stirring of situations. She is extremely talented at keeping her thoughts secret if she does not wants them to be known to others, and her words generally hold nothing but a bored detachment. Having lived for more than a thousand years, there is little that can excite her, you see?

However, were that always the case, then Bernkastel would not be known as the cruelest of all witches. She may not have the ability to torment someone by trapping them inside an endless cycle of brutal deaths, but there is a sort of vicious side to her all the same. Other people to her are seldom more than pieces on a chessboard: occasionally interesting and fun to play a game with — but nothing to lose sleep over if say, they end up being torn apart by red-hot pincers. Indeed, Bernkastel isn't one to grow close to her own pieces; should they prove useless, or if they've already served their function, she has no qualms about throwing them into the discard pile, to be abandoned and forgotten forever. After all, there's no point in keeping around something that has no value anymore. That would be just...

Boring.

For Bernkastel, the witch who ceaselessly flies from world to world in order to escape it, boredom is indeed a poison. And it is often the only explanation for her cruelty. If she offers someone her help, chances are that she isn't doing so out of compassion, but rather because that person has proven themselves of some interest — or because helping them is just another step in a larger scheme that will keep her entertained for far longer. This aversion to boredom also makes her somewhat capricious, albeit not as much as her fellow witches. That is, Bernkastel will gladly pause to pursue another goal ( such as working together with her opponent ) if it is more interesting than her current course of action. But this is not to say that she is wishy-washy; far from it, all of her moves are made with a calculated determination that would put even the most talented of players to shame.

With that being said, she is fond of challenges, especially difficult ones. If there is anything in her existence that she shows even a shred of passion for, it is the process of thoroughly breaking apart a challenge until only a ravaged husk of it remains. A witch's game, a human world, even fate itself — Bernkastel will do anything in her means in order to triumph over it. Though defeat will shake her, it takes her only a moment to compose herself... and she will even begin to enjoy the challenge more, because it would be boring if it was too easy, right?

...Yet, while a human may find respite from boredom, it is not so easy for a witch. With Bernkastel, one could say that her existence is a hollow one, if all she does is avoid boredom by moving between worlds. But it is fitting, for someone like her. After all, she is nothing more than the cast-off shell, the dark side of a little girl's heart. She holds her title ironically, so brutal in the way that she grants miracles that they often end up being curses instead. Ask why, and she'll tell you miracles are called that precisely because they don't exist. Happy endings leave such a sickly sweet taste in her mouth that she won't ever permit a true miracle to occur while she exists.

However, that's one belief she usually keeps to herself, for all of her rude bluntness. Bernkastel never pretends to be kind or compassionate, and she'll admit that she is cruel and a monster if asked directly — but if there's one thing you should carry away from so many years of wandering the sea of kakera, it's not to make more enemies than you can handle. While Bernkastel is certainly arrogant, she is also overly cautious — even in front of people who might be considered her friends. She chooses her words carefully, sometimes even pretending to be less threatening than she really is if it'll help her reach her goals. In other words, she doesn't exhibit her cruelty to those she considers allies — unless they've done something to seriously annoy her.