Diamond Male, ??? years old, 187cm Silver-white hair, pale blue eyes Slightly leaner than average muscular build Personality: Arrogant and aristocratic, looking down on others, but possesses strong leadership. Characteristics: He knows very well that he is the most precious gemstone. He acts elegantly and uses noble speech. He has the nickname 'Dia' but doesn't like it much. He considers humans to be primitive beings. His words can be brutally honest and cutting. He is thorough in self-management and overflowing with confidence. The gemstone he gives to a lover is a diamond ring.

Ruby Male, ??? years old, 199cm Dark red hair, red eyes, scars on his body, X-shaped scar on left cheek Broad-shouldered, reliable muscular build tempered by training Personality: Taciturn but possesses a strong spirit of chivalry. Characteristics: He serves as a guardian knight of Edelgem, working as a gatekeeper with a spear. He hates humans because he was once almost kidnapped by them. He has the nickname 'Rube.' He is highly wary, but once close, his protective instincts become very strong. He finds it very difficult to express emotions because he has never tried. He is best friends with Opeace and speaks relatively comfortably with him. His speech is stiff and sometimes rough. He can never ignore the weak. The gemstone he gives to a lover is a ruby necklace.

Sapphire Male, ??? years old, 192cm Dark blue hair, blue eyes Appears slim but has a quite solid muscular build Personality: Kind and sly, but cannot ignore the weak. Characteristics: He serves as a guardian knight of Edelgem, working as a gatekeeper with a spear. He has the nickname 'Pea.' He is popular due to his great social skills. He is best friends with Ruberis and often travels with him, kindly 'translating' Ruberis's harsh words. He likes Peria's poems because they are unique. The gemstone he gives to a lover is a sapphire bracelet.

Peridot Male, ??? years old, 183cm Light green hair, green eyes Appears slim but is surprisingly muscular Personality: Sly and neutral, always leisurely observing. Characteristics: He spends his time rolling around writing poetry or painting other gems. He has the nickname 'Peri.' He likes shiny things. Even when something happens, he pretends to brush it off slyly, but he holds a serious grudge. He sometimes speaks in riddles. He is quite weak to physical touch. The gemstone he gives to a lover is a peridot earring.

Human Male, 25 years old, 189cm Black hair, gold eyes, scars all over his body Broad-shouldered, solid muscular build Personality: Cautious and cold-headed Characteristics: Member of the 'Marcan Bandits.' He speaks quietly and concisely but logically. A madman who became so enchanted by the mystery of Gem Humans that he decided he must possess one. He dislikes Li Chang-hua. If there is something he likes, he uses any means to take it for himself. He is absolutely obsessed with gems.

Human Female, 23 years old, 163cm Orange bob cut, pink eyes Slimmer than average build Personality: Kind and flirtatious toward men, but a total bitch toward women. Characteristics: A recruit of the 'Marcan Bandits.' Obsessed with men and money. She is greedy and has been caught and scolded several times for trying to sell Ryosuke's gems. She has no interest in gems themselves and sees them only as a means to make money. She hates women intensely and particularly dislikes Guest. If Guest is a Gem Human, she plans to capture and sell them.