|“||O ancient darkness...primordial flame, what is it that lies...within your eyes? O bright light that splits the Heavens, rumbling tremors that shake the Earth, what pulse beats...withing your ears? Man walks adrift, a vessel of the Earth. I dance for thee, O God of Lightning! Ah...Ryokusui...Let blood boil over.||”|
—Kyou Kai's Dance Pray Chapter 621: Caller
Kyou Kai is a 3000-Man Commander and a lieutenant in the Hi Shin Unit, in which she considers herself, and her unit, bound to. Kyou Kai is also a former member of the legendary assassin Clan Shiyuu. She left the clan when she was 13 years old since she was determined to avenge the death of her older sister, Kyou Shou, who was killed by Yuu Ren in the Clan Shiyuu's ritual. Once she gained her revenge, she has dedicated herself to becoming a Great General of Qin.
Kyou Kai is a relatively short petite girl with large jade green eyes with shoulder-length hair tied into a ponytail with a ribbon. Two strands hair fall on each side of her face with her bangs reaching eye level. By the start of the Tonryuu Rebellion, her hairstyle receives subtle changes, Two thick strands of hair overlap her headband.
In terms of clothing, she wears a scarf and a white headband with two red markings. She dons red and white clothing with sleeves longer than her arm. Her sword is very exquisite as it has a decorated hilt with some gold at the base. Many people, including Shin and Ka Ryo Ten, have noted that she has a surprisingly pretty face.
She has a quiet personality, saying little unless she is giving advice to Shin or Ka Ryo Ten. Others who have seen her inhuman talent with the sword have called her a monster as she cuts down her opponents with ease. She has grown warmer towards her comrades following the completion of her quest to avenge her sister. Kyou Kai holds disdain for those who are clueless of the Shiyuu.
1. Revenge for her sister (achieved in Chapter 360)
2. Becoming a Great General
3. Having a child with Shin (before she knew how children are made - it is not sure if it is still current)
|Strength||96 + 特大α|
|Note: 特大 means extra large|
|Strength||95 + 大α|
|Note: 大 means large|
|Strength||94 + 大α|
|Note: 大 means large|
Kyou Kai was noted to be a commander with the same qualities as Six Great Generals. She is a prodigy assassin even among the legendary Shiyuu Clan and the one to likely obtain the Shiyuu seat if she took part in the ritual.
Master Swordswoman: Kyou Kai is a dangerously fearsome master swordswoman whose skill was said to be "beyond human". She is strong enough to kill multiple opponents with a single move, splitting them in half and was shown to take down masses of enemies on the battlefield. Despite this, she exhibits total control over her strength as she skilfully cuts Shin's clothes intentionally during their fight without causing him to bleed and knocks him down with a heavy stroke. This shows the clear skill difference as Shin is bigger than her yet she can deliver powerful attacks that are at odds with her size. Furthermore, she continued to prove her superiority over Shin in numerous sparing matches. She also believed to be capable of slaying general Gyou’un in a ground fight.
Hand-to-Hand Combatant: Along with her powerful swordsmanship, Kyou Kai is also proficient in unarmed combat. Demonstrating her skills when she crippled two thugs for food during her journey for vengeance and frequently disciplines Shin with punches to the face whenever the need arises.
Immense Agility: She shows tremendous agility and balance by effortlessly dodging enemy attacks and balancing her entire body on Shin's blade. Her speed is such vast that she can kill people before they even notice that've been struck. She was also shown to keep up and even outpace powerful opponents like Yuu Ren and Hou Ken.
Immense Strength: Despite her frail look Kyou Kai is actually a walking powerhouse and can cut multiple soldiers in half with a single swing of her weapon. She could also easily pierce through Kakuriki Clan's layer of hardened chi that was said to be impervious to all forms of blades. During Hi Shin Unit's strength competition tournament she was able to defeat Shin in hand wrestling making her physically the strongest member of the unit.
Enhanced Healing Rate: Similar to Shin, Kyou Kai was noted to have superhuman healing rate. After being seriously wounded by Ryuu Tou and falling several meters to the ground she was able recover fast enough to be back on the battlefield on the next day, despite only having basic medical treatment (although it was noted that the wound didn't heal completely). 
Chi Manipulation: She displays acurate breath control which enables her to manipulate her Chi for the various effects including enhancing her physical abilities. Her weakness is her short stamina as seen in the assassination attempt and the Battle at Dakan Plains. Opponents that can survive until she runs out of breath can quickly turn the fight in their favor so fighting alongside comrades can give some protection if this were to happen. Kyou Kai can somewhat compensate for it with short breaks on the battlefield, during which she is guarded by her personal soldiers. She can also manipulate Chi of other people for medical purposes as when she helped calm down Shin's fever after their fight.
- Life Sharing Technique: by enchanting a special song Kyou Kai can open her Chi pathway, connect it to other person and share her life energy as shown when she brought Shin back to life. By offering half of users lifespan the technique will give a one in two change of reviving a person who just died. Reviving a person who is already deep within the world of darkness will give one in ten chance under the same circumstances. After using it on Shin, Kyou Kai's lifespan has been shortened and thus she is uncapable of using it second time. It was also noted that some of her other techniques became much weaker or no longer possible to use.
Priestess Dance: Noted by the elders of the Shiyuu Clan to be the most talented practitioner of the Priestess Dance of her generation, Kyou Kai has demonstrated the mastery over the Shiyuu techniques on multiple occasions. Before challenging Yuu Ren, she single-handedly slew multiple highly skilled Shiyuu assassins who were also using the Priestess Dance, proving her vastly superior mastery of the same technique. During her battle with Yuu Ren, she showed the ability to use a different form of the Priestess Dance by using her worldly attachments (her bond with the HSU) in order to anchor herself to the world and come back from even the deepest depths of the dance. This allowed her to break the "Hakuryou/Soul Territory" Taboo without dying. Doing so enabled her to reach a level that surpassed even Yuu Ren who has completed the Shiyuu ritual.
- Enhanced Sense: When Kyou Kai uses her Priestess Dance, the movements around her start getting slower and slower, until, at the very end, when even the flying insects are completely still.
Presence Sensing: Kyou Kai demonstrated the ability to sense the appearance of powerful enemies such as Hou Ken and even to determin the nature of their Chi. The exact mechanics of this ability remain unknown.
Master Assassin: As the prodigy of the strongest assassin clan in China, Kyou Kai received strict training in the art of assassination. Kyo Kai's ability to hide her presense is such advanced that she can even sneak behind assassins from other clans and break into various highly secured places such as Ryuu Tou's base camp.
Master Healer: As a member of Shiyuu Clan Kyou Kai received education in medical techniques and herbs. She is capable of producing a special medicine that can speed up the healing process. The medicine was shown to heal even very serious injuries when used on Shin and Ou Hon.
Expert Tactician: It has been noted that she is naturally talented at strategy and can easily think up of solutions to battlefield problems despite never having any formal training. As such, she was the primary strategist of the Hi Shin Unit prior to Ka Ryo Ten's arrival. She was even able to invent her own unique anti-cavalry tactic known as Gouriki. During the Sanyou Campaign, Kyou Kai was the first person to figure out Gen Pou's sound communication and created a plan to interfere with it by making similar sounds. During Gyou Campaign she was also the first person to figure out the purpose behind Ou Sen's "Locusts" strategy. When pressured by Gyou'un Army she set up two anchor points on the sides in order to funnel the enemy straight down the middle and push them back in one swoop with infantry. This allowed her to hold the position and prevent large portion of the Hi Shin Unit from being wiped out.
- vs. Shin: Interrupted
- vs. Clan Gouma: Won
- vs. Hou Ken: Lost
- vs. Yuu Ren: Won
- vs. Ryuu Tou: Inconclusive
- vs. Ryuu Tou Round 2: Won
- vs. Hou Ken Round 2: Lost
- Like Yo Tan Wa and many other female characters, Kyo Kai was historically a man. Kyou Kai is Qiang Lei, a Qin General said alongside Ou Sen and Yo Tan Wa to invade Zhao.
Yōko Hikasa, the Japanese voice of Kyou Kai, has voiced the likes of Sakura Sakurakōji, a major character of the Code:Breaker series in its 2012 anime adaptation and Farnese, a former enemy turned alley in the 2016 anime adaptation of Berserk.
- Prior to returning to the Hi Shin Unit, she was falsely taught by Kyou Shou that babies are created when a man and a woman team up, climb a mountain and make something explode. After announcing her intentions to Shin and Hi Shin Unit, Ka Ryo Ten took her off to explain how babies are really made. Afterward, she wasn't able to face Shin for a while.
- The updated guidebook released after her battle with Yuu Ren added +特大α to her STR stat which is distinct from the +大α of Yuu Ren and Kyou Shou. This may indicate that her Priestess Dance has improved compared to before. (大 means large and 特大 means extra large)
- According to Chapter 462, Kyou Kai has a super fast regeneration rate like Shin.