In English there are no masculine or feminine forms. English uses gender specific nouns for male or female.
The gender specific noun for a male is hero.
The corresponding gender specific noun for a female is heroine.
Footnote: Use of many gender specific nouns for females have begun to fall out of use by society, since there is no reason to distinguish between the sexes in occupations and professions, there is no need for the old fashioned female designations.
In English there are no masculine or feminine forms. English uses gender specific nouns for male or female.
The noun 'heroes' is a common gender noun, a word for males or females.
It is heroine, but hero is the modern gender-neutral term commonly used nowadays.
Heroine
heroine
The feminine form of "heroes" is "heroines".
The plural form of the noun hero is heroes.
The feminine form of ami is amie. The feminine plural is amies.
Mistress is the feminine form of master. It is already in feminine form.
The feminine form of a baron is a baroness.
The feminine form of alumnus is alumna. The feminine plural is alumnae.
The feminine form of charmant is charmante. The feminine plural is charmantes.
The feminine form of bajo is baja. The feminine plural is bajas.
The feminine form of benefactor is benefactress.
The feminine form of groom is bride. The female partner in a marriage.
The feminine form of the name Ronald is Ronaldine.
The feminine form of grandfather is grandmother.