She is voiced by Chisa Yokoyama in the Japanese version of the anime and Tara Sands in the English version.
Biscuit likes to act and look like a young girl. Her overall aspect is reminiscent of a porcelain doll. She is often shown wearing a sleeveless dress and a bloomer with a mantelet and skirt donned over it, along with gloves and plain leather shoes. She always has her hair tied-up neatly and has changed its style 3 times throughout the storyline.
In her true form she is a massive and extremely muscular woman several times the size of her preferred form. Although she claims to stay in her younger form to have the enemy underestimate her, the main reason is that she hates her original appearance. Regardless of which form she is in, Biscuit is very powerful. However, she does receive a tremendous power boost when she reverts back.
She has brown hair and blue eyes. In the 1999 anime her hair is a lighter brown than in the manga and in the 2011 anime her hair is blonde and her eyes are pink.
Biscuit has a devious personality. She initially uses her cutesy appearance and demeanor to her advantage whether it's for information gathering, getting what she wants, or even in combat by acting innocent and helpless so most people will usually put their guards down around her. However, as a teacher of Nen, she has a stern and serious attitude towards her students. She's also prone to violent outbursts whenever she is left out of a conversation or reminded of her true age (with Killua often being the victim because of his wisecracks about it). She is also shown to be a pervert, as she enjoys the view of Hisoka being naked when he was bathing in a lake, while the other people in her party are shown to have disturbed reactions. As a Treasure Hunter, Biscuit loves collecting rare jewels (and gets very excited about them, and has a habit of naming them) and getting money. Though in the beginning she was out to destroy Gon and Killua's friendship, at the end of Greed Island she acknowledges (albeit, in her head) that she's close to developing parental feelings toward the two of them.
Not much is revealed about her past, except to the fact that she was Wing's Nen master — the man who introduced Nen to Killua and Gon — and that she used to be an examiner in the Hunter Exam. According to herself, she started to learn Nen at the age of 17.
Greed Island arc
Her goal in the game was to get a gem that can be only found on that island called "Blue Planet". She was intrigued by Gon's attitude and decided to observe the young hunter until they encountered Binolt, a Blacklist Hunter turned murderer. She came to conclude that Gon and Killua will get themselves killed if she left them alone. After defeating Binolt, Gon and Killua asked her to put her jewel hunt on hold and teach them Nen, which was already her intention. Biscuit taught the two about the advanced techniques of Nen which took three months before doing any actual Specified Slot Card hunting. When Killua left the island to take the Hunter Exam, Biscuit and Gon trained alone to develop Gon's Hatsu abilities which resulted in three Jajanken techniques. After Gon and Killua was able to master the advanced Nen technique, Bisky let them clear the game. After achieving more than fifty Restricted Slot cards, they were recruited by Kazsule to stop Genthru from clearing the game. They then lead to Soufrabi to attain the restricted card # 2. During their first encounter with the Greed Island Convicts, she challenged the Pirate footballer but intentionally lost. After gaining information on the games played with Razor's team they made a stronger team by adding Goreinu, Hisoka and Tsezguerra's group to face Razor and his fourteen Devils. When they one three consecutive wins, Razor challenges them to an 8 vs. 8 dodgeball match. She also participated in the dodge ball tournament.She did not receive any damage but was out since her dress was hit by the ball. She then told Gon to beat Razor even if it costs him his life.In the battle with the Bombers, she faced Bara. She used Accompany to transport the both of them to Soufrabi. She told Bara that she's much stronger than him and landed a number of hits on him. Even though she knew that she would instantly win over Bara, she let him land a strong hit on her face before her transformation. After returning to her true form, she instantly defeated Bara. She also noted that she hated her normal form because it was too macho.After beating all the bombers, they used Angel's Breath to heal Gon, Killua, Bara and Genthru. Then Goreinu gave Tsezguerra's cards to the trio so that they could complete 99 of the restricted cards. To get the Ruler's Blessing, all players of Greed Island were given a quiz but Biscuit did not participate. When Gon got the highest score, he was given an invitation to the capital Limeiro. Biscuit and Killua accompanied Gon to the castle.She was then later seen in the festival event for players who have cleared the game. After the event, Gon asks Biscuit what card she would like to take with her when they leave the island and she stuck with her dream of getting #81 Blue Planet. When they were outside the game, she uses gain to get the gem and names it Planet-chan. Afterwards, Gon and Killua part ways with her after she declines to continue on their adventure to find Ging.
Chimera Ant arc
After the events of Greed Island, she made her return after being invited by Palm Siberia to help Gon and Killua train for their battles against Knuckle and Shoot in their attempt to return to NGL to rescue Kite.
The training routine is as follows:
- Maintain Ren for 3 hours everyday, to increase their ability to do so in battle longer.
- Challenge Knuckle into a duel after being exhausted by step 1
- Quickly recover through her ability, Magical Spa Services（まじかるエステ,Magical Esthétique）
She also gave Killua some advice about his inferiority complex when facing stronger opponents. She then bails after seeing Palm because she was unsure of Gon's chances of victory vs Knuckle.
13th Hunter Chairman Election arc
Following the will of the late Chairman Netero, Biscuit also submitted her own vote for the election. She is also among the hunters that went to check on Gon who is in critical condition after his battle with Neferpitou. On the the election for the 13th Chairman seat, Biscuit is in the 16th place on the first election, 13th place on the second, 12th place on the third, 10th place on the fourth, and finally 9th place on the fifth where she was taken off the list of candidates because only the top 8 will be able to continue on the sixth phase of the election.
Biscuit has introduced Nen exercises to develop her students' hatsu. Here are some of them:
- Level 1- Rock Breaking
The student enhances a rock's durability using "Shu" and "Ko" to repeatedly smash a specifically large number of rocks as much as possible within an allotted time to clear. The student will typically go from start to finish once a day until they reach their goal number without failure.
- Level 1- Nen Numbers
The student runs while trying to shape his/her aura on his index finger from 0 to 9 within an allotted time, repeating the practice with the intent of shortening the amount of time it takes to go through the numbers while using little concentration, paying attention to what's in front of you, thus the running.
- Level 1- Aura throwing
The student first prepares a specific distance and object as a targeted goal and practices emitting a small ball of nen, maintaining its shape and prolonging its duration. Once the student has a grasp of emitting and maintaining his/her aura for a certain duration the student sends the ball of nen flying towards the destination. The student will repeat attempting to throw the aura ball towards the target until it reaches the intended goal. The more a nen user has practiced their "Ten" and "Ren" the easier it is learning to perform aura throwing.
- Level 5- Levitation by Aura Emission
The student needs to position into a one arm handstand and emit an aura strong enough to launch his/her body off the ground. The student will repeat the exercise until a predetermined height is reached.
Abilities & Powers
Biscuit is an incredibly skilled fighter. She has yet to show her full power, but she still managed to defeat troublesome opponents such as Binolt and Bara single-handedly, with them growing terrified at her true abilities. Even Killua, who is on her side, dreads her strength. She has yet to show any offensive-oriented special ability, as the combination of her extensive knowledge in Nen, honed body and martial artistry have been enough to dispatch her enemies. She is also endowed with a bright intellect.
Enhanced strength: Biscuit's strength is superhuman. Even without reverting back to her original appearance, she was able to send Binolt flying dozens of meters away, knocking him out in the process, with a single palm thrust on his back without using Nen, claiming that he would have died otherwise. When she disengages her ability, her punches become so powerful that one of them, despite seemingly not carrying the whole body's brunt, but just the arm's, crushed Bara's face and struck him unconscious immediately, also raising a large curtain of dust.
Enhanced speed and reflexes: When they didn't know her true identity, both Killua and Gon praised Biscuit for keeping their pace while running through the forest. Later, she slapped Killua without him being able to catch a glimpse of her movement. When she defeated Bara, he didn't have the chance to stop or avoid her punch. Biscuit also managed to dodge a sneaky ball thrown by Razor that, pretending to be aiming at Killua, had rigged it to warp in her direction: even with the very small distance, she avoided direct contact, although her gown was incinerated.
High intelligence: Biscuit is very smart, analytic and knowledgeable, especially regarding Nen. She can devise impeccable methods of training and she is a very quick learner herself, as proven during the dodgeball game with Razor, where she managed to make her ball change direction right after seeing the technique. Thanks also to her experience, Biscuit is a praiseworthy tactician, with her predictions being often accurate. However, she herself recognizes Killua as superior in this field.
Proficient in hand-to-hand combat: Since her adversaries have not been a match for her so far, her degree of mastery in this field is unclear. In her fight with Binolt she dodged his attack and at the same time flipped him over. Furthermore, having had a sparring match with Killua, a tremendously capable martial artist himself, and coming out of it completely unscathed, she must be fairly good in close combat. Having been Wing's instructor, she might be the one who trained him in Shingen-ryu kung fu.
Biscuit's proficiency in Nen is such that she can successfully coach others, developing effective training schedules for her disciples. Proof of her knowledge and skills is the fact that she was an examiner of the Hunter Exam at some point of the past. Moreover, she was Wing's and occasionally is Gon and Killua's teacher. She is well versed in every principle of the art and can mix Transmutation, her Nen class, Manipulation and Conjuration in the same ability, but has proven herself to be able to use Emission and Enhancement to a high degree as well.
- Biscuit's harsh training methods and ability to change her physical appearance using her energy makes her very similar to the Yu Yu Hakusho character, Genkai.
- She's also similar to Izumi Curtis. Both are middle-aged women who serve as a mentor to the two main protagonists, have very harsh training methods and are very sensitive about their age, to the point that they freak out whenever they're called "old".