The Fire Archer Eidolons are labelled 'Medium' in the main window, but "Heavy" (and not Eidolon) in the summary pane.
It's Retold, the remaster that came out late 2024.
I'm playing as the major god Demeter, the fourth major Greek god that was just released this week. A fourth Norse major god, Freyr, was also released alongside the initial release of Retold.
Those weird green units are Eidolons, resurrected units as a result of Persephone's god power, Persephone being one of Demeter's Mythic Age minor god options.