Regulus

Regulus also known as Alpha Leonis is one of the brightest stars in the night sky located in the "heart" of the constellation Leo and is approximately 79 lightyears from Earth's Sun. It is usually visible at its brightest from Earth for stargazing during the spring season, starting in April.

Its name comes from Latin and translates to "Little King". Many other cultures in ancient times associated the star with kings, due to it shining brighter than other stars and the fact the lion, the shape that the constellation Leo forms, is both a symbol of monarchs on certain family nobility crests or associated other symbols of power in different cultures.

Kamen Rider Zi-O
The Regulus star plays a role in the prophecy of Oma's Day, as it shines abnormally brighter than normal and is at its highest point of visibility prematurely by three weeks. Black Woz states that this is because of the star's symbolic nature to royalty as "the star of kings", heralding the arrival of Oma Zi-O.