"Once I Called You Brother..."

A song/fic of Megatron and Optimus Prime. This short story shows flashbacks to when life was good, and when the sworn enemies were best friends. And then when life seems tough, Megatron looks back to the days when he was called Megatronus, and when Optimus was called Orion Pax. One day, towards the end of this story, Megatron makes a grave mistake, one where he will always feel guilty of until the day his spark goes out.