User blog comment:Nyonne/12 Guardians of the Gods/@comment-27360323-20160120134337/@comment-24974484-20160120135831

Reddit and AI are your friends. You can also googling by typing "(name of unit) 7 star lore

For manga, yes, they exist. Cirno translated it IIRC, or you can find the Japanese ver instead : http://ganma.jp/grangaia