Who is Fallen in Transformers: Revenge of the Fallen?

Ancient Decepticon Prime seeking to destroy Earth.

What are Fallen's abilities?

Fallen's abilities include ancient magic, energy manipulation, destruction.

Fallen has 3 mapped relationships in Transformers: Revenge of the Fallen. Explore the interactive relationship map for details.

Fallen — Conflict Chosen Opponent — Sam Witwicky (Shia LaBeouf)
The Fallen treats Sam as the key obstacle to activating the Star Harvester.

The Fallen demands that Sam be handed over, and Sam ultimately uses the Matrix to help defeat the Fallen's plan.
Fallen — Conflict Arch Enemy — Optimus Prime (Peter Cullen)
Optimus is the decisive opponent preventing the Fallen from destroying Earth.

The Fallen seeks to activate the Star Harvester, while the revived Optimus destroys it and kills the Fallen.
Fallen — Power Master And Servant — Megatron (Hugo Weaving)
Megatron serves the Fallen's plan and carries out his commands.

After being resurrected, Megatron returns to the Fallen, who sends him to kill Optimus and capture Sam.