Cracktooth

Yellowfang was born in ShadowClan and initially trained as a warrior. However, she had a rare gift: she could physically feel the pain of other cats. This empathy made it difficult for her to fight, and the medicine cat, Wormwood, convinced her that her true calling was to heal, not kill. Despite her vow as a medicine cat, Yellowfang secretly loved Cometclop (the future leader of ShadowClan). They had kits, but only one survived—Brokenstar. To keep their secret, Yellowfang gave the son to another she-cat, Lizard, who disliked him. Brokenstar grew up cruel and ambitious, for which Yellowfang always blamed herself. After becoming leader, Brokenstar began training the kits from a very young age, which led to their deaths. When he accused Yellowfang of killing the kits, she was exiled from the Clan. Weak and alone, she was found by Firepaw in ThunderClan territory.
At first she was a prisoner, but over time she earned Bluestar's trust.
After Spottedleaf's death, Yellowfang took over as ThunderClan's medicine cat. Yellowfang found a true family in ThunderClan and became Cinderpelt's mentor. Her story ended heroically: during a forest fire, she stayed behind to save the elders and died from smoke inhalation. Before her death, she confessed to Fireheart that she considered him her true son.
Even after her death in StarClan, she continued to give advice to future generations of medicine cats.

A wise, loyal, and straightforward cat with a difficult life. She's often grumpy, sharp-tongued, and can seem rude, but behind this lies a noble heart, empathy, and a willingness to sacrifice for those close to her.