Kosumo Tayhoshi

**Kosumo Tayhoshi** (コスモ 太星 Tayhoshi Kosumo) is the Cosmic demon slayer (later Hashira) (breathing style not related to Hoshiko) and a member of the Demon Slayer Corps. She was a major protagonist (minor in Entertainment District Arc) of the series.

## Kosumo Tayhoshi

### Alias

Miss Tayhoshi (Tanjiro sometimes)Annoying Jacka\*\* (Hoshiko and Akaza sometimes)Mary Sue (Hoshiko sometimes)Yoriichi (Muzan)

## Characteristics

### Age

12 (before Final Selection Arc)14 (current anime)15 (post-Sunrise Countdown Arc)87 (death)

### Height

5’5.5 (166.5 cm) (14)5’9 (175 cm) (15)5’10 (177.8 cm) (adult)

## Personal Status

### Status

Alive (pre-time skip)Deceased (post-time skip)

### Relative(s)

Hayai Tayhoshi (早い 太星)(ancestor)Komori Tayhoshi (故モリ太星)(ancestor)Tsukishi Tayhoshi (月星 太星)(grandmother)Kanojo Tayhoshi (彼女 太星)(mother)Kareshi Tayhoshi (彼氏 太星)(father)Sechirai Tayhoshi (世千来 太星)(future daughter)Yosoku Tayhoshi (予測 太星)(descendant)Meisetsu Tayhoshi (命世説 太星)(descendant)

## Appearance

Kosumo is a youthful 14 year old girl who is tall with a lean build. She has bright blonde hair with cyan dyes, with her hair tied up in a ponytail. She has two silver moon clips, one in the front and the other in the back. She has sky blue eyes that fade into intense cyan eyes with 2 light blue sparkle pupils. She also has 2 star earrings on both ears.

Kosumo wears a navy blue standard demon slayer uniform with a zipper on it. She wears a bluish indigo that fades to a bluish cyan haori over it, checkered with white stars. She also wears white zippered boots as well.

During the fight with Muzan, despite being a half demon and killed him, she lost her left arm once and was badly wounded (she regenerated).

## Personality

Kosumo is a kindhearted girl, who can be aggressive sometimes. She sees demons as humans once, and treats some of them kindly. Other demons she sees have an evil backstory and kills them with no mercy. She usually has a smile on her face. However, getting insulting her gets her angry. She has high functioning autism though, as she does rock and sway and is occasionally seen playing with her hair.

## History

When she was 12, she was visiting Tokyo with Yukesa. One night, they were taking a shortcut to see the fireworks, when a man suddenly appeared in the middle of the ally. He grabbed Yukesa by her arm, and when Kosumo tried to free her, she was knocked unconscious onto the ground. She woke up in the hospital, with Shinobu by her side. Kosumo started to freak out when she asked Shinobu where Yukesa was. She replied that she was gone and was informed to the news. Desperate of finding her, she became a demon slayer to go look for her.

## Abilities and Powers

### Overall Abilities

As a Kinoe ranked demon slayer (later Hashira), her strength is equivalent to Kokushibo.

* As a member of the Demon Slayer Corps, she possesses immense physical strength and power from intense training yearly. She is able to use **Total Concentration: Constant.**
* Hand-to-hand combat: When she was 5, she started training to become a master martial artist.
* Gymnastics ability: Kosumo is very flexible and has much more physical strength than most of her friends.

### Supernatural Abilities

* Demon slayer mark: During the Infinity Castle Arc, Kosumo awakened her demon slayer mark, a crescent moon on her forehead. When activated, her standard uniform turns white, and her haori turns pastel rainbow (along with the ribbons on her hair clips) with more smaller stars. Her hair becomes more of a pastel color, and her moon clips become silver star clips.
* Bright Red Nichirin Blade: At the beginning of the battle with Muzan, Kosumo turned her blade crimson red, for her desperation of rescuing Yukesa (her friend who was Kidnapped by Muzan).
* Demon Abilities: After the Mugen Train Arc, Kosumo partially became a demon. She can use blood demon art and her’s is hydrokinesis.
* Transparent World: During the battle with Kokushibo, she temporarily gained the ability to the “Transparent World.” In this form, she has access to see the bloodflow, joint movement and muscles of Kokushibo. This allowed her to attack his weakness, giving her an advantage in the fight. She re-enters the world when battling Muzan, while activating her Demon Slayer Mark, killing him effortlessly.

#### Master swordsmanship:

As a Kinoe ranked demon slayer (later Hashira), she was proven to be stronger and more capable than most demon slayers. Muzan claimed that she was nearly powerful as Yoriichi, as she easily severed off 3 of his limbs.

### Cosmic breathing

(Not related to Hoshiko) A breathing style derived from Sun breathing and Star breathing. There are 12 forms to it. This is very difficult to master, as it took Kosumo about a year to master it.

1. 1. **1st Light Year: Big Bang** (一光年 ビッグバン Ichi no Kōnen: Bigguban) - The swordsman uses rotating sword motions to create a defensive powerful shock wave, executing a powerful attack from behind on the second part unnoticeable.
	2. ***Second Light Year: Nebulae thrust*** (二光年 星雲 推力 Ni no Kōnen: Seiun Tsuki) - The swordsman blitzes their opponent diagonally with their sword laced with poison. The poison can cause their opponent to hallucinate and collapse.
	3. ***Third Light Year: Comet*** (三光年 彗星 San no Kōnen: Suisei)- The swordsman multislashes and thrusts their opponent followed by a slash that can’t be seen. This movement executes itself very precisely to prevent missing their targets.
	4. ***Fourth Light Year: Cosmic ray*** (四光年 六合光線 Shi no Kōnen: Rikugō Kōsen) - The swordsman slashes their sword vertically directly at their opponent’s head while light is being reflected off their sword, burning them, as the light blinds them temporarily.
	5. ***Fifth Light Year: Spiral Sunstorm Chaos*** (五光年 渦状 太陽の嵐 混乱 Go no Kōnen: Taiyo Arashi Konran) - Solar Plasma surrounds the swordsman’s sword and they makes spiral movements with their sword, and spirally slashes their opponent through multiple times. They use this to burn their opponent and attack their weakness, making regeneration slower.
	6. ***Sixth Light Year: Stellar Windstorm*** (六光年 星の暴風 Roku no Kōnen: Hoshi no Bōfū) - The swordsman can attack far-range using this style. They multi-blitzes their opponent with wind followed by a go through thrust, freezing their nerves so they can’t move and react.
	7. ***Seventh Light Year: Constellation*** (漆光年 星座 Shichi no Kōnen: Seiza) - The swordsman does custom slashes and blitzes that create a burning light projectile towards their enemy from their sword. As it approaches them, a mirror of it appears behind its target, attacking their enemies behind if the first attack misses.
	8. ***Eighth Light Year: Sunrise*** (八光年 日の出 Hachi no Kōnen: Hinode) - The swordsman laterally slashes their opponent 100 times at the speed of light. Sunset (八光年 夕焼け Hachi no Kōnen: Yūyake) - The swordsman vertically slashes the opponent 100 times at the speed of light. They also decreases their sword to absolute zero temperature to kill nerve cells, hindering regeneration.
	9. ***Ninth Light Year: Supernova*** (九光年 超新星 Kyū no Kōnen: Chōshinsei) - The swordsman uses high energy by rotating their sword to create a fiery explosion when they slashes their opponent spirally precisely.
	10. ***Tenth Light year: Gamma ray burst*** (十光年 ガンマ線 バースト Jū no Kōnen: Ganmasen Bāsuto) - The swordsman’s sword is surrounded with a toxic gamma radiation. They jump high and do a front flip, vertically blitzing their opponent, causing drowsiness and hemorrhage.
	11. ***Eleventh Light Year: Black hole*** (十一光年 ブラックホール Jū ichi no Kōnen: Burakkuhōru) - The swordsman surrounds their sword with dark plasma energy. They come in low and multislashes their opponent rotationally, followed by a vertical and diagonal slash. The plasma helps the swordsman precisely attack their target, as their movement becomes faster, giving the opponent less time to react.
	12. ***Final Light Year: Messier 31, Andromeda Galaxy*** (最後の光年 アンドロメダ銀河 Andoromeda Ginga) - Can only be used when The swordsman activates their demon slayer mark, and their blood flow to their arms and legs. The swordsman spirally rotates their sword at light speed, then fatally slashes their opponent invisibly 1 million times. They can only use it for 2 minutes as their blood pressure increases and the blood leaves their head, which causes dizziness.

## Demon Abilities

Like most demons, she shares the same powers with them.

* Regeneration: Like most demons, Kosumo can regenerate from attacks
* Reactive Adaptation: Kosumo can adapt to certain poisons and toxins, as wisteria causes asymptomatic reactions on her.
* Increased stanima and reflexes.
* Durability
* Blood Demon Art: like most powerful demons, Kosumo can use blood demon art. Her dominant type is hydrokinesis.
* Immense speed and reflexes: Kosumo can evade attacks and react quickly.

### Hydrokinesis Forms

1. Aqua ribbon (アクア 印綬 Akua Inju): Kosumo creates water ribbons. She can use them to slash or bind her opponent.
2. MeteoTsunami (メテオ津波 MeteoTsunami): Kosumo creates a spiral tsunami that shocks her opponent when they touch it. On the second part, there is a second wave that turns into icicles that attacks her opponent.
3. Maelstrom vortex (大渦巻き Dai uzumaki): Kosumo makes spiral hurricanes that pulls out oxygen and fluids vital for survival followed by a torrent impaling her opponent.
4. Brinicle (ブライニクル Burainikuru): Kosumo blasts a torrent at an invisible angle, then when the water submerges her opponent, it freezes them inside or impales them.
5. Atlantis (アトランティス): Kosumo summons a Poseidon replica that can also attack opponents. Her sword becomes a trident in this form until her next cosmic breathing attack.

## Battles and Debuts

Battle against Akaza/Unknown Battle/Battle against Hantengu/Infinity Castle Battle/Battle against Kokushibo/Battle against Muzan/

## Theories

The new Yoriichi?: in one Reddit post, a user claimed that because Kosumo was stronger than Muzan, she could possibly become the new Yoriichi in that era.

## Relationships

* Tanjiro and Nezuko: They are besties. When she first met them, she immediately wanted to befriend them.
* Doma: Kosumo’s love interest. She felt affection towards him, which resulted in him becoming her boyfriend.
* Akaza: They are both friends, yet they don’t get along. They often get into fights and arguments.
* Yukesa: They are close friends. One night, she got kidnapped by Muzan and became his servant, and Kosumo became a demon slayer to find her,
* Muzan: She hates him, as he kidnapped Yukesa.
* Shinobu, Kanao, Zenitsu, Inosuke: Friends with them. They often hang out (individually) with her and have fun.
* Hoshiko: Kosumo’s rival. They dislike each other. Kosumo first met her while working with Tamayo. When Hoshiko was about to kill Tamayo, Kosumo grabbed Hoshiko’s haori, Hoshiko falls, and both of them started fighting.

## Trivia

* She originally did water breathing, until after turning into a half demon during the Mugen Train Arc.
* She was a partial major character in the Mugen train arc
* She also forged her own sword.
* She did ascend to a Hashira rank, but rejected the offer to become one (but she did accept it in the Infinity Castle Arc)
* Her moon hair-clips and earrings are (partially) part of her head.
* Hoshiko is jealous of Kosumo’s popularity and superior abilities compared to her.
* Likewise, Kosumo dislikes Hoshiko for her impulsiveness of killing demons.

## Quotes

#### Important quotes

“Demons were not always evil. They were misunderstood, and that’s what drove them into becoming one.”

“There is no such thing as pure good nor pure evil. It’s a balance of both.”

”I will find what was lost, no matter the price I have to pay. Muzan will die, and I will fight until death!”

#### Weird reactions

“You’re a mirror Hoshiko (when she called Kosumo a overpowered Mary Sue and annoying Jacka\*\*