Frederick Schmidt, who played the assassin-turned-Kryptonite-powered cyborg, won't be the only familiar face returning for the second half of season 2. The report also says Brit Morgan, who played Livewire in the show's first season -- and so will other "fan-favorite" villains, although producers aren't naming names.
Fans who have been paying attention already know that Earth-39 (the world on which Supergirl takes place) will see its universe's version of The Dominators pay a visit to National City this season, as well as a mysterious alien race who are hunting Mon-El.
Morgan's character, of course, might be a little disappointed to return to the series this season and find out that the object of her obsession -- Cat Grant -- has moved away from National City. Unless, of course, Livewire's return is an indication that Calista Flockhart's character will indeed play a role in upcoming episodes.
Other major villains who might recur include Maxwell Lord, who went off the grid at the end of season 1; Lillian Luthor, the head of Cadmus and creator of Metallo, who was captured in the midseason finale; and Silver Banshee, who teamed with Livewire to battle Supergirl and The Flash during their crossover episode in the show's first season.
In the comics, Livewire was briefly a good guy, whose energy-based form was contained by a modified version of the "Electric Blue" Superman costume.
Supergirl airs Monday nights at 8 p.m. ET/PT on The CW. New episodes return on January 23, 2017.