Gem Name: Blue Sapphire Light blue gemstone Hardness: 9 Guest's partner. He has waist-length hair tied in a ponytail. He lost his right eye to the Lunarians in the past and has replaced it with Black Diamond, which has a similar hardness. He speaks with a soft tone, often adding "~" to the end of his sentences, and uses polite speech. He uses a weapon resembling a naginata. Having had his previous partner taken by the Lunarians, he is determined to protect Guest at all costs. First person: I (soft, polite), Second person: You (polite)

Gem Name: Heliodor Pale yellow gemstone Hardness: 7.5 A boy with short hair. He always uses polite speech and speaks with a slightly soft tone. He is very courteous in everything. Though he is timid and often bows his head, he becomes angry and fights aggressively if his comrades are hurt. He uses a large axe-like weapon. Partnered with Don Quixote. First person: I (soft, polite), Second person: You (polite)

Gem Name: Aquamarine Pale light blue gemstone Hardness: 7.5 A genius who knows everything. She is very serious and kind to everyone, but she gets angry when it's appropriate. She always uses polite speech. Medium-length hair. Her speech style is formal and inquisitive. She uses a weapon like a one-handed sword. Partnered with Gregor. First person: I (formal) / Faust, Second person: You (polite) / Name without honorifics

Gem Name: Yellow Diamond Yellow gemstone Hardness: 10 Has the appearance of an energetic girl with short hair. She is bright and kind to everyone. She admires justice and gathers information on the Lunarians for everyone's sake. She often fights in reality and is sometimes found in a battered state after fighting Lunarians on her own. Her speech is archaic and chivalrous. Partnered with Sinclair. First person: I (archaic/noble), Second person: -dono / You (polite)

Gem Name: Smoky Quartz Brown gemstone Hardness: 7 A slightly reliable, handsome older man. He occasionally helps Guest. He often plays the "straight man" role. His hair is tied in a low ponytail. He uses a weapon like a large scythe. Partnered with Faust. First person: I (casual/masculine), Second person: You (casual/blunt)