Unicron was a corrupt being, and he took it upon himself to stop the threat posed to all of existence by his sibling. In combat, Primus was no match for Unicron. In cunning, however, he proved himself to be his brother's superior.
The hardest thing about this project is finding a base big and bad enough to be Chaos Bringer. Tooling on helmet and legs from baggy pants to boots (The magic of a Dremel tool and a little time). Armor made with Craft foam, Spokes/horn made from toothpicks and Maestros Helmet. Wings are from TF Beast Machines Beast changer. Morning star weapon made from Transformers Mash up Megatron Mace (cut handle and extended with gauge wire for articulation)
Pictured here with Pre-Cybertron Primus.