Majo Shuukai Anthology Comic

A life together started on a witch's whim. Witches who give and witches who take. In the time they spend together, what kind of changes will those who change bring to the witch who never changes? A collection of short stories about witches and the children and messengers they've found.

(Source: REX Comics, translated)

Note: "Let's Meet at The Witches' Gathering" (#魔女集会で会いましょう) was originally an artistic participation hashtag on Twitter where authors depicted before/after comparison images of a witch who raised a child into adult.