Shinies
Beings of good who are composed of light energy. Aiden reveals, in Season 5, that the Shinies are ghost children that have crossed over into The Light. He also comments that there are more Shinies than there are Shadows, and that if they were to go to war with each other, the Shinies would win. The Shadows prevent their growing numbers by consuming still-earthbound ghost children, making the Shinies fear them. But in the episode "The Children's Parade", Aiden reveals that if he, along with the other Shinies, use their combined power, they can defeat the Shadows forever.
In previous seasons, the Shinies have already revealed their presence to Melinda without her knowing. Carl, a Watcher, tells Melinda that she is surrounded by "light beings" watching over her and they are shown all throughout Grandview, watching over her during her wedding vow renewal. In later events, Melinda notices Aiden talking to himself. But later events reveal that Aiden has the ability to see these spirits (the Shinies), which she cannot see. Cassidy Peyton, a ghost girl Melinda crossed over, becomes a Shiny after going into The Light and becomes good friends with Aiden.
Shinies are attracted to "shiny things" such as flashlights, utensils, etc. Also, the Shinies are afraid of the Shadows, as depicted in the season 5 episode "Lost in the Shadows".
In the series finale ("The Children's Parade") the Shinies, led by Aiden, destroy the Shadows once and for all.
Read more about this topic: List Of Ghost Whisperer Characters, Shinies and Shadows