Expansion

The Expansion is the great plan of the Cybertronians of the Dead Universe. Their goal is to expand the power of the Cybertronians out among the galaxy, influence cosmic events, and spread the greatness of Cybertron to the lesser beings.

"The Expansion is upon us! Nothing can stop it! Not you or I!"

- Galvatron

IDW comics continuity
The Expansion had its origin over 6.7 million years ago, during the reign of Nova Prime. Believiing that the Transformers were the highest form of life, Nova believed that they should expand their influence across the cosmos. He commissioned the Ark under the pretense of exploration, secretly planning a conquest. However, Galvatron, one of the crew members, directed the Ark into the Dead Universe portal in the Benzuli Expanse. The full truth of their time there is unknown, but Ark crew was driven to a state of living death, and Nova became the fearsome being known as Nemesis Prime. Needless to say, the Expansion was put on hold.

Millions of years later, after Cybertron was laid waste and Optimus Prime was leader of the Autobots, Nightbeat travelled to Gorlam Prime, where he was apprehended by Galvatron and others. Nemesis decided that it was time to prepare for the Expansion, placing a device in Nightbeat's cerebral chamber. He also sent Galvatron to retrieve Thunderwing from Hound's unit on Cybertron, killing Leadfoot in the process. After this, Galvatron was dispatched to Earth to prevent the Reapers from destroying it, as Earth was part of the Expansion.

When Jhiaxus finished the Nega-Core, Nemesis Prime dispatched Cyclonus to prepare it for activation, using Thunderwing as its guardian. Learning that it was almost ready, Nemesis Prime ordered his minions to prepare for the Expansion.