Darklight

Darklight is a Decepticon character in the Generation 1 continuity.

Rar! I'm a monstah!

Darklight was a Decepticon assassin who attempted to murder Optimus Prime during the early stages of the Great War. He wielded an energy sword.

Fiction

Dreamwave Comics

Along with Backbite and Umbra, Darklight invaded the Chamber of the Ancients in Iacon, just as Optronix accepted the Matrix of Leadership and became Optimus Prime. Wielding Umbra's weapon mode, Darklight fired on the new Autobot leader and informed him that Megatron himself had ordered Prime's death. Releasing his fellow assassin, he continued to engage Prime until he was accidentally slain by Umbra.

From Teletraan I: The Transformers Wiki, a Wikia wiki.