|“||Love is fickle and fleeting.||”|
Not much is known about Tsukiko's life before the circus, but is known that she was a former student of Mr. A. H-, as well as the winner of her challenge. Her opponent was a woman named Hinata, who she loved more than anything in the world. Tsukiko was declared the winner of her challenge after Hinata set herself on fire, killing herself. Tsukiko mentions that prior to Hinata's death, her element was water, but she changed it to fire to honor Hinata.
In 1885, Tsukiko appears uninvited at a midnight dinner held by Chandresh Christophe Lefevre, where she reveals her skills as a contortionist. Impressed, Lefevre hires her for the circus and she becomes a regular for the midnight dinners. Chandresh often uses her performance to describe the essence of the circus he aims to create.
Tsukiko reveals her history with the challenge to Celia Bowen in 1901, and gives her one year to make the circus entirely independent lest it completely derail after the end of the challenge. Tsukiko also alludes to the nature of Celia's romance with Marco Alisdair, suggesting that their connection as competitors is what's causing the romance.
In 1902, Tsukiko organises a meeting with Marco, telling him about the circus's predicament and suggesting that he must sacrifice himself in order for the circus to continue running. However, as she prepares to trap him within the courtyard cauldron, Celia intervenes by causing the circus to freeze, which extinguishes the cauldron fire. Later, Tsukiko meets with Bailey Clarke, but says that she cannot help him restore the circus and that she is only an 'emissary' for him.
The last time Tsukiko is seen is after Bailey takes on responsibility for the circus - he is told by Celia to use Tsukiko's lighter to ignite the cauldron. Tsukiko agrees, telling Bailey to be careful with the lighter as it belonged to someone dear to her.
Tsukiko is described as a small (but not tiny) woman with long black hair tied into two elaborate braids on her head. She has long rows of symbols tattooed on her skin that snakes around her body - these tattoos are her 'notes' from her lessons with Alexander, since she wanted to avoid getting ink-stained fingers like Marco.
Tsukiko has a scar that shows her binding to her challenge, like Celia and Marco. However, Tsukiko's scar is at the nape of her neck, in the curve of a crescent moon.
It is not known how old Tsukiko is exactly, but it is made clear that she is extremely old - she reveals to Marco on October 31st in 1902 that she won her challenge '83 years, 6 months and 21 days ago'. This would mean that she won her challenge on April 20th in 1819.
Tsukiko is a rather calm and mysterious person, never directly answering questions unless you carefully pick your choice of words. However, she is also caring, as shown when she comforted Isobel. According to Celia, she always seems to know more than what she lets on.