Marius Messer IV (2625-2641) was the only son of United Empire of Earth (UEE) Imperator Livia III and her husband Daniel Scota, a former pilot. He spent his childhood on Earth (Sol III) with his cousins, Gammon and Illyana. His grandfather Deacon II tutored him privately from a young age; Marius would often accompany his mother and Deacon II on their regular tours of the UEE. After attaining his Equivalency at age 16, he was accepted to the United Empire of Earth Naval Flight Academy (UNFA). He died alongside his father Daniel in a shuttle crash, when their vessel suffered a catastrophic failure upon atmospheric re-entry over Moscow, Earth. Livia III granted him the honorary title of Imperator before retiring from public life in 2643.