10 Most Underrated Arrowverse Villains

One of Supergirl's most recurring foes is also one of her most dangerous. Lillian Luthor has proven herself to be as conniving and dangerous as her son and is arguably one of the Arrowverse's most dangerous villains despite not having a storied comic history nor fantastical abilities.

The Luthor matriarch has gone toe-to-toe with Kara since the second season and has come very close to coming out on top. Some of her achievements include heading Project Cadmus, heading Luthor Corp, and in the rare turn to the side of good, help thwart the Daxamite invasion.

However, her time in the light was short-lived and she went back to her criminal ways. This escalated after the Crisis on Infinite Earths saga where she and Lex capitalized on the latter's sanitized public image to go up against Leviathan and acquire the power of the organization's leads for themselves.

Unlike most villains on this list, Lillian is still alive/not reformed and there is room for her to prominently feature in Supergirl's final season and give the Girl of Steel various challenges along the way.