We will discuss about Tamayo’s backstory in this blog post. Tamayo was one of the oldest demons in Demon Slayer. She is said to be more than 500 years older chronologically. Even though she was a demon for so long, she restrained herself from eating humans.
Tamayo even devoted her life to researching demons and making medicine to cure herself and other people.
She was kind, wise, and had a lot of intelligence. She spent most of her life studying the science behind demons and how they change, so she was one of the people in the series who knew the most about the subject.
Even though the relationship between humans and demons is usually pretty bad, she was very kind to humans.

Here we will see how Tamayo’s backstory on how she was turned into a demon and what she did about it.
Tamayo Backstory as a Human
Tamayo was a married woman with several children. Apart from this, there is nothing much shown about her in the manga about her. Tamayo’s backstory as a human must be a simple one with general hardships and everyday struggles.
She didn’t face any disaster or drastic struggle in her life during her childhood years. But, during her later years, she fell ill with the condition that had the potential to take her life.

Tamayo Meeting Muzan Kibutsuji
It was during the course of her search for treatment that she initially came into contact with Muzan Kibutsuji. When Muzan offered to assist Tamayo, he made it appear as though he had already cured her disease.
Muzan Turning Tamayo Into a Demon
As soon as she stupidly accepted, he immediately transformed her into a demon and released her into the town to cause havoc.
During the course of her murderous rampage, she not only took the lives of her husband and children but also a great number of other individuals. She was unable to pull herself out of her dark sorrow after she realised what she had done to her family.
Tamayo Backstory as a Demon
Tamayo was finally indentured as Muzan’s servant. This is demonstrated when Muzan approaches Yoriichi Tsugikuni and subsequently fights him, as she remains next to Muzan and did nothing while he speaks with the Demon Slayer.
This most likely indicates that at some point, Tamayo attempted to kill Muzan to exact revenge on her family and that he succeeded by transforming her into a demon.
She most likely did not prevail in the battle, and the Demon Lord, upon realising how much stronger he was than she was, probably broke her spirit. This resulted in her becoming his servant.
Muzan Fights Yoriichi
When Tamayo witnessed the battle between Muzan and Yoriichi, everything began to shift. His mind was absolutely blown by the might of the Demon Slayer when he witnessed the Demon Slayer completely defeat and slay the Demon King.
As soon as she realised that Muzan had been vanquished and was very close to passing away, the raging urge that she had to kill and humiliate him returned.

Tamayo was furious that Muzan could escape by dismembering himself. He was also upset that Muzan was able to escape and that he appeared to be immune to being beheaded. Because of these thoughts and the fact that Yoriichi saw a gleam of hope in Tamayo’s eyes when Muzan was almost vanquished, Yoriichi decided not to murder Tamayo.
Yoriichi Lets Tamayo Go Free
They found common ground in their loathing of Muzan and became allies as a result. He did not kill her and instead let her go free. In the end, he was punished by the Demon Slayer Corps for both failing to kill Muzan and allowing her to escape.
Tamayo Taking Up a Different Lifestyle
Tamayo discovered that she could sustain her life by consuming the flesh of dead animals and people when Yoriichi let her go. She recalled that Yoriichi had told her that he believed in her determination to beat Muzan. Because of that, she fought against her natural tendencies and refrained from attacking humans, despite the fact that it was painful.
After some time had passed, she regained her mental clarity and organised her life so that she could investigate the physiology of demons and look for treatment.
Tamayo devotes two hundred years of her life to learning about medicine, and by the end, she has acquired sufficient knowledge to modify her body so that she no longer needs to eat people to survive.
When Yushiro first encountered him, she was ill and had nowhere to go. She utilises the same way she did to change herself into a demon in order to transform him into a demon with his approval. Since that time, Yushiro has been her dependable and trustworthy defender.

Final Thoughts – Tamayo Backstory
Though leading an okay life from childhood to adulthood, Tamayo faces a terminal illness. She was deceived into becoming a demon, killing her own family.
This was particularly tragic as she couldn’t channel her anger towards anyone apart from Muzan, who saved her life and herself, who killed everyone in her family after becoming a demon.