The Dominators Will Return on 'Supergirl' — Here's Why That's Scary
Though the heroes of The Flash, Arrow, Supergirl, and DC’s Legends of Tomorrow were able to thwart the Dominators in the four-way crossover,...

Here’s where the scary part comes in: In the comics, specifically Invasion, the Dominators were not alone in coming to Earth. More the politicians and planners, the Dominators assembled a coalition of other alien races, including the Thanagarians, the Khunds, and the Daxamites, to invade Earth.

That last race should sound familiar: Mon-El (Chris Wood) hails from Daxam. Could the reveal in the Supergirl winter finale that an unidentified alien race is hunting Mon-El be connected? Here’s a theory: That mysterious alien race could be among the coalition, who sent Mon-El ahead to Earth-38 to observe the planet before the armada arrives. After all, the Daxamites in the comics join the coalition in the first place as observers only before eventually joining the fight.