According the Worldmind, the Luminals are a series of corps which protect and defend emotions. They act as either police forces of peace or soldiers of war. There is 7 different corps.
The red luminals, demons of rage.
The citrus luminals, thieves of greed
The gold luminals, monsters of fear
The green luminals, soldiers of courage
The blue luminals, monks of peace
the violet luminals, tribesmen of sorrow
and the rose luminals, warriors of love
the rose luminals are the first luminals seen. Each corps is formed by millions Of alien creatures who all gain powers through the luminous bands. The bands look for corpsmen across the universe and are attracted to stronger emotions.
On Knowhere, the Luminals had many run-ins with the Guardians of the Galaxy including many misunderstandings, as the Luminals strictly follow the rules set by Chairperson Gorani.
When the Luminals investigate the Fault without the cooperation of the Guardians, they unleashed a creature from another dimension that's only purpose was to cause death. It killed the Luminal Massdriver before Moondragon was able to take the creature inside of her and control it psionically. The Luminals demanded justice for the death of their teammate and detained Moondragon. Before a hearing could take place, Cynosure and Moondragon (who were cuffed together) were kidnapped by the Matriarch and the Universal Church of Truth.
The Luminals and the Guardians teamed up and successfully rescued their teammates. After this, the Luminals and the Guardians put their differences aside, the Luminals even stating they would leave Knowhere if the Guardians were cast out.
The luminals wield the luminous bands. Cosmic gauntlets which can give the user vast energy manipulation. They seem to be sentient and can discard themselves from the user if their respective emotion is dying. For example if a red luminal feels love their bands fly away. The bands allow the user to fly, phase through objects, turn invisible, release energy beams, create force fields and other physical powers. Their main power however is the ability to create hardened light constructs of any size, shape, and complexity. They can create simple constructs like weapons or complex ones like planets. The constructs durability hinges on how strong the users respective emotion is. For example a red luminals construct will be stronger if his rage is high enough.
All seven of the corps are nearly identical to the emotional spectrum of dc comics. Green luminal is identical to green lantern etc.