The Mother of Quirks is how she came to be known posthumously the mother of Chikara Yotsubashi, also known as Destro, founder and former commander of the Meta Liberation Army. She got this title because she was the first person to use the word "Quirk" to describe Meta Abilities.
Not much is known about her appearance, except that she was a woman with long, light-colored hair.
From what is known of her, she was an affectionate mother to her son, whom she always loved and protected, despite being born with powers in a time when prejudice against Quirk users (Metas) was at its worse. Aware of the situation of discrimination that people with special powers suffered, she also showed great willpower to fight against quirk hatred, wishing for a world where no one is despised by his powers, despite being ridiculed and detested for her ideals.
Destro's mother lived during the era of chaos where the quirks (known as meta abilities at the time) were feared and quirk’s users hated. She gave birth to Destro, who, having a quirk, began to be discriminated against and despised.
When her son Chikara was born, she had to see how he was marginalized and scorned because he was born with a power. She spoke out against this discrimination by claiming that his power didn't make the kid a monster, his power was simply one of his "Quirks". She begged people to change, to make a world where her child and others with powers have the same rights and considerations as everyone else. Her words fell on deaf ears, and she was murdered by an Anti-quirk faction.
Over time, the government co-opted her words when they brought order back to the world, and the Quirks were accepted. Therefore, the woman became known as “The Mother of Quirks". However, the acceptance of the Quirk was accompanied by quirk regulations that restricted their use. Chikara Yotsubashi felt that the government had stolen the words of his mother without understanding what she truly wanted and rebelled against the regulations. He went on to found the Meta Liberation Army under the name "Destro" in order to defend his mother's wishes.