Kirara

was Sango's faithful nekomata companion and main method of transportation.

History
Kirara was originally the companion of Midoriko, the miko who created the Shikon no Tama, suggesting that she was far older than she seemed, which made her the oldest member of Inuyasha's group. Sometime later, she became Shako's family companion, was passed down by Shako to Sango's father, and then by Sango's father to Sango when she was still very young.

During the Story
When Kirara was first introduced, she was greeting Sango after she had come home from a mission. She was then seen playing with Sango right before she and the other yōkai taijiya went to Hitomi castle and were slain. Sango helped fight to protect the demon slayer village during the attack, ending up as the only survivor. She was discovered by Myōga during this time, and joined Inuyasha's group on their search for Naraku's castle. During the search, Kirara reunited with Sango, who ordered her to kill Naraku if he did anything suspicious.

After these events, Kirara traveled with Inuyasha's group and acted as an ally and friend through the entire series. Kirara became fast friends with Shippō, often seen in his company when Sango wasn't around. When someone was depressed, Kirara often allowed them to rest on her for comfort.

When Kohaku was brought back to life by a Sacred Jewel shard, Kirara was ordered to kill Naraku to break the spell on him; however, she ended up badly poisoned by his miasma after biting his shoulder. She was later cured of the poison thanks to Jinenji's antidote.

In Kirara Come Home, it was shown that Kirara was, at times, abused by Inuyasha, Kagome and Miroku for their own selfish needs; Inuyasha accidentally burned some of her fur off while practicing the Wind Scar, Kagome used her for quick transport to the Bone-Eater's Well while forgetting promised cat treats to return the favor, and Miroku used Kirara to stage demon attacks to meet women. Despite this, she appeared to hold no grudge towards them, and the group felt deep regret for their past actions.

Shown in Kohaku, Sango and Kirara: The Secret Flower Garden, Kirara had many fond memories of her time living with Sango and Kohaku in the demon slayers' village. She met Kohaku during this time, and learned he was free of Naraku's spell. She heard Kohaku wishing that Sango could see the field of lilies near the village, so Kirara led her there.

Three years after Naraku's defeat, Kirara joined Kohaku as a traveling companion on his quest to become a more powerful demon slayer.

Personality
Since Kirara was a cat demon, she acted similar to regular cats: eating cat food, treats, fish, and playing with cat toys, as well as having cat-like weaknesses. Kirara was shown to be very intelligent as well as sentient. She was fiercely loyal to Sango, but with time, she showed loyalty to all members of the group.

Kirara demonstrated exceptional patience, often honoring the requests of the group and their various friends. For example, she allowed Inuyasha to practice the potentially lethal Kaze no Kizu attack on her, leaving bald spots on her fur. In addition, she helped Miroku impress village women and ward off the undesired advances of the older village women. Kagome admitted to playing dress up with her, and using her to return to the Modern Era without the knowledge of the rest of the group.

Physical description
Kirara usually appeared to be a small kitten-sized feline with red eyes, a marking on her forehead, and two tails. However, she had two forms: one of a small kitten, and a larger one resembling a saber-toothed cat. In her full-sized demon form, flames emerged from her feet and tails, and her power increased considerably, allowing her to battle even the strongest of demon opponents.

Powers & Abilities

 * Transformation: Kirara had the ability to transform from a small kitten to a larger cat resembling a saber-toothed cat. Whether she was transforming into the huge cat or back into the little kitten, she was engulfed in flames, which, after disappearing, revealed which form she was changing into.
 * Flight: When transformed, Kirara had the ability to fly. She was capable of carrying three grown adults at once, but it tired her out quickly.
 * Enhanced Strength: When transformed, Kirara was very strong, several times managing to overpower many other foes, including larger demons.
 * Enhanced Speed: When transformed, Kirara's speed increased considerably. She was able to keep up with Entei and even with Inuyasha at top speed.
 * Enhanced Durability: When transformed, Kirara was very durable, managing to endure a practiced Kaze no Kizu from Inuyasha while he was practicing on her of her own free will, emerging fairly unscathed with only a part of her fur shaved off.
 * Enhanced Endurance: When transformed, Kirara could fight continuous battles against many foes for a considerable amount of time before tiring out, which in turn forced her to transform back into her small kitten form.

Allies/Traveling companions
Due to their long past, Sango and Kirara were very loyal to one another and cared for each other greatly. They have always had a wonderful friendship and strong bond. Kirara often tried comforting Sango when she was sad, offering the comfort of her fur to ease Sango's pain. Since Miroku came into the picture, Kirara became fearful of Sango's anger.
 * Sango

Kirara helped Inuyasha fight his enemies, and they often worked together. Sometimes, she acted as his "trusted steed", allowing Inuyasha to ride her into some fights with sword drawn. Inuyasha respected Kirara, knowing she was a reliable ally.
 * Inuyasha

Kagome treated Kirara as her own, and sometimes Kirara helped Kagome fight demons. Kirara often got cat food and treats from the Modern Era as thanks from Kagome, which she enjoyed greatly. However, she was sometimes a victim of Kagome's dress-up games because of how cute her kitten form was.
 * Kagome Higurashi

Miroku didn't seem to have much of a relationship with Kirara, although she did help him get the attention of some local village girls in one episode by pretending to attack a village, even chasing off old women interested in Miroku. She apparently didn't hold a grudge towards him for using her. Kirara often carried Miroku on her back along with Sango.
 * Miroku

Kirara was particularly close to Shippō, who were often seen playing together. This was probably because of their shared connection of both being demons. Kirara was often seen with Shippō on her back when the others weren't riding her, most likely protecting him. At times when Sango was frightening, Kirara and Shippō held each other.
 * Shippō

Other
Having lived with Kohaku most of his life, Kirara was close to him as she is to Sango. However, their relationship was quite strained due to Kohaku being under Naraku's control most of the series. In an anime-only episode, Kirara met Kohaku once he had broken free of Naraku's spell, and fought demons alongside him in perfect combination. She honored Kohaku's desire to have Sango see a secret lily field, leading her there. Following the three year time skip, Kirara acted as Kohaku's partner in his quest to become a stronger demon slayer.
 * Kohaku

Trivia

 * When Kirara entered water, the fire on her tail and legs did not go out.
 * In the anime, it was shown that Kirara had been in Sango and Kohaku's family for at least three generations, as she was seen accompanying their grandfather and father.
 * In the anime, it seems Kirara was also the partner of Midoriko.
 * Kirara apparently had very impressive eyesight or senses. In Episode 136, when Sango was invisible, Kirara was able to precisely jump onto Sango's shoulder and put the balls into her hands.
 * Kirara's voice actor was the same as Sugar's from Urusei Yatsura, another series by Rumiko Takahashi.