Transformers: War Within: The Dark Ages

Optimus Prime and Megatron are missing, presumed dead, the civil war for control of Cybertron has degenerated into a dark cauldron of confusion and turmoil, splinter factions clashing in endless border skirmishes. Into this potent powder keg of a divided world comes The Fallen, a Transformer from the planet's prehistory... with dark designs of his own!