From Gineipaedia, the Legend of Galactic Heroes wiki
The emperor's full set of titles as of 796 UC (487 IC / 3596 CE) were:
- Ruler of all humanity.
- Sovereign of all the universe.
- Defender of the order and laws that govern the heavenly realm.
- Kaiser of the sacred and inviolable Galactic Empire.
The Galactic Empire's emperors were descendants of the Goldenbaum Dynasty, whereas the New Galactic Empire's emperors were potentially descendants of the Goldenlöwe Dynasty. (Legend of Galactic Heroes Volume 1: Dawn)
In the Galactic Empire, Ruduolf intended that his throne be passed down patrilinealy through the eldest male offspring. By the end of the dynasty, however, an absence of heirs led to the selection of an infant girl as the Goldenbaum's final emperor.
In the New Galactic Empire, emperor Reinhard von Lohengram was succeeded by his wife, Hildegarde von Lohengramm, who became Empress, but it is unknown how the line of succession was formalized thereafter. Reinhard, however, was an ardent believer in meritocracy, and decreed that if his son were not capable, he should not inherit the throne.