The Ko'erst use Tachyon Circuits to travel vast distances across space. When a new world develops Tachyon technology, they connect with the world and use their Telepathy to control somebody on that world to keep the transfer open so they can invade the planet.
When S.T.A.R. Labs began developing the technology, the Ko'erst began controlling Forsythe to keep the transfer open so they could invade. Superman however stopped them, tying them up before they were sent back through the transfer.
- Batman v Superman: Dawn of Justice: Playground Heroes (First appearance)