Matsu

Matsu was the daughter of village headwoman Shirasawa. She was infected by a species of mushi, which eventually led to her death. Her son, Maho, would also be stricken with the same illness.

Appearance
Matsu was a woman with dark hair and pale skin.

Life
While not much is known about her life, she did mention to Maho that she visited a volcano with Maho's father on their travels. Then, it is presumed they both returned and settled in the village where her mother lived before she gave birth to Maho.

Illness and death
Matsu first became infected with the Ah during winter, two years prior to the events of "The Soft Horns." Over the course of the next year, her infection would slowly drain the life from her until she was completely bedridden.

As her disease progressed, she was often seen covering her ears, presumably to block out the loud noises produced by Mushi. However, it was revealed later during Ginko's investigation into Maho's illness that she had figured out the Ah's weakness on her own and was attempting to fight back. Her condition, however, was too advanced and her body too weak for it to make a difference.

Just before her death, the loud noises she had been hearing for a year stopped suddenly, although her horns remained. Instead of feeling elated, the loss of noise made her panic. Before dying, in an attempt to keep her son from suffering the same fate, she covered his ears and had him focus on the sound, telling him to do the same whenever he was in pain or felt scared. Ironically, this would later end up allowing the Ah to infect Maho.

Trivia

 * Her name was only revealed in the anime series.