Lumen

Lumens are magical creatures introduced in Season 8 that guard the core of planets and stars.

Overview
According to Stella, Lumens are peaceful creatures of pure light that live inside the stars. In every star/planet, there is a village of Lumens. They are said to never leave their stars, unless they have very serious reasons to. Under Valtor's evil spell, they are changed into Staryummies.

Lumens usually live in their village, city or tribe. They may keep Star Cats as pets, like Lumilla has Lumino as her pet.

As mentioned by Twinkly and Obscurum, Lumens cannot swim except for the Gorgol's Lumens.

Appearance
Lumens are the size of a baby with fair skin with different hairstyles, a pair of glowing eyes with star-shaped highlights, and cheeks with pink blushes. They wear dresses. They have a hairband and sparkly, star/five-petal flower-shaped accessories on their hair. Though their hair usually stay in a ponytail behind the big accessory, hair styles, colors of their hair, hairbands and dresses and accessories (if have any) are varied. They go barefoot.

Lumenia
Lumenia's Lumens have golden/blond hair, navy blue eyes and fair skin. They wear orange dresses and star-shaped accessories of matching color. Their headbands are blue. Twinkly is the only Lumen there to wear red headband.

Peripla
Peripla's Lumens have whitish blue hair, navy blue eyes and extra fair skin. They wear whitish blue dresses and light cyan star-shaped accessories. Their headbands are yellow. The captain of the ship has tan skin and brown eyes. She wears a navy blue dress with two golden epaulettes and has sapphire blue star-shapped accessory, which is decorated by a golden anchor. She does not wear any headband but a captain cap that is adorned by a brown rope.

Iridia
Iridia's Lumens have blue hair, yellow green eyes and fair skin. They wear bluish purple dresses and star-shaped accessories of matching color. Their headbands are dark blue. Lumilla is the only Lumen there with purple hair and brown eyes, she also has a curly hair strand on each side of her head. She wear purple headband.

Gorgol
Gorgol's Lumens have platinum blond hair, nay blue eyes and fair skin. Unlike Lumens from other stars, Gorgol's Lumens have their bangs stay in side-swept style and adorned with a turquoise seashell, and the rest of their hair is untied. They wear scale-patterned pink bras and body-tails of matching color and pattern. Their star-shaped accessories are in lighter pink shade. Their headbands are turquoise and decorated by dark turquoise pearls.

Hypsos
Hypsos' Lumens have sea green hair, green eyes and medium skin tone. Their bangs are also in different style in comparison with Lumens from other stars as their bangs are rougher and more divided. They wear blue star-shaped accessories and navy blue headbands. Their dresses are in dark-navy-and-light-gray checkered pattern.

Syderia
Syderia's Lumens have brown hair, golden brown eyes and green skin tone. They have orge-like traits (as mentioned by Knut), with their fangs visible and have wooden clubs as their weapons of choice. They have a beaded hair stran on each side of their head. They wear orangish yellow fluffy, fur-like headbands, and green star-shaped accessories that adorned by the same material with their headbands. Their dresses are in a darker shade of green, with the hems slightly torn. They also wear brown bead necklaces decorated by a white small bone in the center.

Sun
Sun's Lumens have dark brown hair, dark blue eyes and fair skin. They wear golden galeae with sun symbol carved in the middle of the galeae, and their star-shaped accessories are red. They wear silver body armors and reddish copper, skirt-like lower body armors. They have fencing swords as weapons of choice.

Monoceros
Monoceros' Lumens have magenta hair, brown eyes and fair skin. Their bangs are similar to Hypsos' Lumens, though the bangs are less rough and less divided. They wear light-turquoise-and-cream-colored diagonal stripe dresses, with a cream-colored layer of ruffles, and light turquoise star-shaped accessories. They wear golden headbands. On each headband, there is a golden horn in the middle and there are two horse-like ears on each side of the headband. Asteria is the only Lumen there to have white strands on her hair. She also wears dark magenta, blue and purple flowers on her headband. The horns are also their weapons of choice.

Coralya
Coralian Lumens have brown hair, navy blue eyes and tan skin. Their bangs are combed and their ponytails are much longer and larger than those of Lumens from other stars. They wear red tops, light green leafy, layered skirts. They also wears orange star-shaped accessories and light green headbands decorated by pink hisbicus flowers. They have cream garlands on their wrists and around their necks. They are often seen moving midair on orangish red surfboards. Coraline is the only Lumen there to have reddish orange hair and green eyes. Her skin tone is noticeably darker than the rest of Coralian Lumens. She wears a yellow top and her skirt is more layered. The garland around her neck is pink while ones on her wrists are orange. She does not wear any headband but a garland made of green leaves and light oranges flower, adorned by a pink hisbicus flower in the middle.

Magical Abilities
Lumens can generate magic stardust and by doing so, they give light to the core of the world they reside in. Lumens reside in different stars and are granted different kinds of magical abilities. Generally, Lumens can absorb all the light energy and then releases an enormous amount of light power.

Some Lumens can shoot offensive energy beams by using weapons, like Monoceros' Lumens with their horns or Sun Lumens with their fencing swords.

Syderia's Lumens, with their orge-like traits, are enhanced greatly in physical strength and they rely on that and their wooden clubs in combat.

The Lumens live in harmony with other magical creatures on their stars as an extended habitat, and even work with them to protect their star. Gorgol's Lumens rely on the magical anemones' defensive system. Monoceros' Lumens have been on a great relationship with Winged Unicorns. Or the Coralian Lumens guard the core with Lava Golems.

Trivia

 * Its name is derived from the word "lumen," meaning "the SI derived unit of luminous flux, a measure of the total quantity of visible light emitted by a source."
 * According to Orion in "Trapped on Prometia," a star will die if there are no Lumens living on it.
 * It is unclear how Coralian Lumens cannot swim when Coralya is an oceanic star.