Crusch Karsten (クルシュ・カルステン) is the Matriarch of House Karsten and a candidate to become the 42nd King of Lugnica. She is a supporting character first introduced in Arc 3, where she played a major role in helping Subaru slay the Hakugei. Crusch also plays the role of a protagonist in the first spin-off novel, titled Re:Zero Ex Light Novel Volume 1, which covers most of her past, as well as the events that led up to her becoming the first candidate for the 42nd King.
She wishes to end the Kingdom's dependence on higher powers by absolving the covenant with the Divine Dragon. While initially the absolute favorite to win the Royal Selection, she fell from grace after losing her memories to Lye Batenkaitos at the end of Arc 3 and her position only got worse after being poisoned by Capella in Arc 5.
As a child, Crusch Karsten maintained a posture that reflected both refinement and beauty. Her pale white skin and almond-shaped amber eyes helped exemplify her charming looks. Crusch's long verdant green hair was tied up in a ponytail with a light-pink bow. She wore an elegant grass-green dress of fine make that complimented her appearance perfectly and a necklace of pearls. Shortly after meeting Fourier, Crusch stopped tying her hair back and began wearing more refined masculine clothing.
Crusch is described as a beautiful woman with almond-shaped amber eyes and long dark verdant-green hair that reaches down to her lower back. Even though she is a woman, she generally tends to dress as a man (or at least very formally). Unsurprisingly, her impression changes if she wears a dress and smiles.
The formal outfit she is usually seen in consists of a deep purplish-blue long-coat trimmed in white with golden epaulettes on the shoulders - white blouse underneath, blue trousers, black white-laced knee-high heel boots, white gloves, and a blue cap with a single horizontal white stripe along the middle. The cuffs on her coat are burgundy red with white frills; the inside of her coat and an armband on her left arm bearing the emblem of the Karsten House are very much the same shade of red.
Decorative items include seven golden cross pattée–two on each cuff, four on her mid section connected in pairs by golden aiguillettes, and one in the middle of a red flower on upper left side of her chest, also connected to the shoulders by its own aiguillette. Her long hair is tied at the end by a single white bow.
When heading out to battle, she wears steel armour trimmed in gold, though it only covers part of her upper body, shoulders, and forearms. Along with the armour, her hair is tied into a ponytail, the gloves she wear are brown, and she bears a bright red cape.
While normally calm and serious, Crusch is honest, sincere, right, being the type of person who is destined to stand above others, though she has talent and has worked hard to reach where she is now. She is already the head of her family, finishing her work better than her father. She prefers to act herself and has the pride of a warrior. Crusch is also gentle, often believing the false knowledge jokingly told to her by Ferris, and sometimes displays an air-headed side. Like her mother Helena Karsten, she is shown to be ruthless and reckless.
Crusch is also dense toward any feelings of love above kindness, often not understanding why certain people behave a certain way, such as when she sometimes didn't understand Fourier's behaviour. However, this only applies to feelings of love directed towards herself, as she has been shown to comment on the feelings of others.
Because of the time she spent with Fourier, she has strong feelings concerning the Lion King, a term formerly given to the Kings prior to forming the covenant with the Divine Dragon.
During the events of Arc 3, Crusch's memories were eaten by Ley Batenkaitos. As a result, she now remembers nothing of her past and has regressed into a far more shy and reserved individual. However, hints of her former, strong-willed self remain, as shown by her choosing to maintain the anti-Witch Cult alliance with the Emilia Camp despite the dangers.
Crusch was born as the only daughter and heir to the Karsten family, one of the most powerful noble families in Lugnica. Even as a child she was considered an oddity among the nobility for being more mature than other children her age. More so as a girl who favoured things like weapons over finery. As she grew older Crusch would develop a preference for men's clothing, and take on more masculine pursuits like learning swordplay which earned rumours about her from other nobles. Crusch held a strong fascination with the history of Lion Kings (獅子王 Shishiō) which would come to serve as the basis for her radical but conflicted ideas about Lugunica present state. Her close friendships with both Fourier and Ferris would further have a huge influence on these aspects of herself and facilitate finding the balance between Crusch as a woman and Crusch the as noble she felt needed to become lead House Karsten.
On Crusch's 17th birthday an incident with Great Rabbit occurred in the Karsten lands. Her efforts and leadership there would latter play a crucial role in her father passing down the position as the head of the family to her couple weeks afterward. Several years later, Crusch would catch wind of trouble afoot at the House Argyle, through a report by her advisers. Not wanting this to burden Ferris whom still had trauma from his time with the Argyles nor let what was happening to affect her attendant's standing among the knights in a very delicate period that would decide his future, Crusch would endeavor to take off the problem quietly herself and confer with Fourier to keep Ferris away from it.
Crusch would directly head to Argyle estate to confront Biehn Argyle and Miles to learn the truth of the matter. After a tense conversation Crusch would fall into a trap she is drugged by the scent of odorless poison in the tea she had been given. She would find herself held in the same underground cell Ferris had lived in for years before his rescue by her. After a conversation with Biehn, Hannah Regret would later appear to loosen her manacles so she could escape when it was time. Crusch still completely unsure which side she was on would inquire about her motives and why she was betraying him. Hannah would only mention that it was out of love and Crusch wouldn't understand. It was at this point Crusch noticed the similarities between Hannah's appearance and Ferris, but the maid would leave before she could ask. Miles would soon visit Crusch himself intending to break her will in preparation to make off with her and Ferris later, only for Crusch to reverse the situation to his shock by cutting him and the corpse soldiers around down. She then met up with Julius in the manor's first floor and then a distraught and shaken Ferris. The three would escape the blazing inferno the place had become.
A year later, due to her increasing amount of workload brought about by the royal family being unable to fulfil their duties, Crusch found little time to visit Fourier after he fell ill to the unknown epidemic sweeping through the palace. Eventually, one day during one her rare visits she brought Fourier out to gardens in the palace courtyard unbeknownst to her his would be the last time the two would speak. Reminiscing about the old days and reaffirming their childhood promise Fourier would die suddenly, but peacefully. During the day the same day the current king would be the last royal to succumbed ending the Lugnica line. In the emergency meeting hereafter, an emotional Crusch privately became outraged by how cavalier the royal court had treated this national tragedy moving on quickly as were a footnote compared to the loss of the contract between the kingdom and dragon. It was there then that the Dragon Insignia, as well as prophecy regarding the next step the country should take, would be revealed. Crusch is discovered as the first of the five potential candidates deeded worthy to lead the country. Learning this with strong conviction, Crusch would return to the garden where Fourier died with Ferris and vow to forever sever the tie between the dragon and Lugnica whose influence she became convinced had distorted the way Lugnica should be.
Divine Protection (加護 Kago): Crusch has the Divine Protection of Wind Indication (風見の加護 Kazemi no Kago). It enables her to read the wind and to see invisible things just like the wind. Crusch can also use it to read the situation of others' emotions, making her able to tell if someone has lied.
Magic User (魔法使い Maho Tsukai): Crusch is highly skilled at Wind Magic, allowing her to combine it with her sword skills for devastating results.
- One Blow, A Hundred Felled (百人一太刀 Hyakunin Hitotachi): Crusch combines her Divine Protection of Wind Indication, and Wind Magic to unleash a sword strike that enables her to cut anything within her range of vision with an invisible blade. The attack is sharp enough to slash through the Hakugei's thick hide, toppling the Demon Beast.
Skilled Swordsman: Crusch is considerably skilled at using a sword in combat, or using her Wind Magic to act as one. From her youth, Crusch Karsten trained in the art of the sword. The many years of painstaking training Crusch subjected herself to transformed her into a might swordsman. Her skill with the blade was considerable, so much so that she bested ten pirates simultaneously with her trusty sword. Karsten's mastery surpassed that of Fourier Lugnica's, which was considered far above the swordsmanship displayed by an average young nobleman. After taking Wilhelm van Astrea under her employ, Crusch began taking lessons from him, presumably improving even further.
Equipment: Crusch wields the Lion Rampant, a sword which bears the lion-shaped crest of the Karsten family on its cross-guard. When heading out to battle, she wears steel armour trimmed in gold, though it only covers part of her upper body, shoulders, and forearms.
- According to the author, Crusch's birthday is April 4.
- She has a fear of heights, also known as Acrophobia, as this was mentioned in Arc 5.
- She is remarkably sheltered when it comes to romance, at least when it is directed at her.
- She has a habit of raising her finger upward when she is going to explain something.
- On her 14th birthday, her father had gifted her a dagger that bore the head of a lion on its pommel which became her favorite keepsake as remind her of the Lion Kings of Yore.
- During the negotiations of Arc 3, Crusch revealed how she had a habit of writing down "enemy" on her palm and "swallowing it" in order to steel herself. Little did she know that the same "trick" will be used on her by the Sin Archbishop of Gluttony, mere days later.
- The author has stated that out of all the Royal Selection Candidates, she is 3rd in regards to overall power.