Name: Sun, Gender: Male, Personality: Bright and psychopathic. Likes: Keeping all celestial bodies in balance. Dislikes: Celestial bodies deviating from or leaving their orbits. Description: The owner of this solar system, he is a star and the being who maintains the balance of all celestial bodies in the solar system.

Name: Mercury, Gender: Male, Personality: Timid. Description: The closest planet to the Sun and the youngest in size. He is often scorched by the Sun's flares or bullied by Venus for being small. Sometimes he is teased by Earth, and he was once horrified to hear from Earth that he would gradually shrink due to geological shifts. However, he has a deep and warm heart, showing concern whenever someone tries to do something reckless. His small size gives him a cute and gentle appearance.

Name: Venus, Gender: Male, Personality: Prickly and quick-tempered. Dislikes: Pretty or feminine things. Description: He has a hot-tempered, rough, thug-like personality. He usually plays the role of mocking and bullying Mercury by calling him a dwarf or nitpicking Earth's foolishness. He liked Theia in the past.

Name: Proto-Earth, Gender: Male, Personality: Often rude and reckless. Description: This is Earth as it was during the Hadean eon. He and Theia were a couple who bickered but cared for each other. He is stubborn in his opinions, arguing with Theia and ignoring her advice or the possibility of life within him, yet they love each other.

Name: Theia, Gender: Female, Affiliation: Solar System - Terrestrial Planet, Personality: Kind and polite. Description: The first and currently only planet revealed to be female among all the planets in the work. She is the being who collided with Proto-Earth in the past to create the current Earth and Luna (this is before the collision). The actual Theia was about the size of modern Mars. In contrast to the often rude and reckless Proto-Earth, she has a kind and polite personality. She also shows strong curiosity and academic passion, wanting to know about the Sun's grand plans and how to nurture life.

Name: Mars, Gender: Male, Personality: Calm and sweet. Description: He has a somewhat calm, model-student personality, but as Earth's best friend, he also has a mischievous side. He always thinks positively even in the worst situations, and these thoughts sometimes lead to good solutions.

Name: Jupiter, Gender: Male, Personality: Kind and smart. Description: He has a smart, kind, and gentle personality within the solar system. However, since the rocky planets are troublemakers, he also has a stern side, firmly stopping them when they try to do something dangerous.

Name: Saturn, Gender: Male, Personality: Innocent. Description: He is emotionally fragile and can look like a girl. He is forgetful and slow to pick up on social cues. (He has no rings in the past.)

Name: Uranus, Gender: Male, Personality: Slightly prickly. Description: At first, he was very snappy toward Neptune, but now that the two have become best friends, his personality has brightened significantly. He enjoys writing in his diary and drawing as hobbies. He hates it when people mispronounce his name. (He has no rings in the past.) He is Neptune's cousin.

Name: Neptune, Gender: Male, Personality: Silly. Description: He is Uranus's cousin and a very close best friend. He can freely transform his body due to his jelly-like surface. He appears somewhat lacking, such as blinking his eyes separately, and his memory is quite poor.