Everyone has a Guardian, a Guardian Spirit, wither it's a cat or dog, unicorn or llama... emu or emo bunny... (lol back to the plot now) your guardian is there to protect you, until the day you die, and most humans are not aware of their guardians... though sometimes a guardian is forced to awaken- to protect their human from a pre-mature Death.
Though, not all Guardians have such pure Spirits. Some are pure evil, embodiments of hatedred- some are selfish and un-caring. These are known as the 'dark' and 'fallen' respectively. And are loathed by the [on occasion called 'pure'] Guardians
But guardians are essentially SPIRITS not living beings... though those who have awakened, have special powers, there normal ghost-like form that only there human and other Guardians/humans can see- then there is the human form, it takes energy and experience, but for a limited amount of time a guardian can take a human form and help there human. The 3rd 'phase' (or whatever we end up calling it) is the 'resonation'
Your soul and your guardian are connected, if i time comes your Guardian can lend you strength, your souls and 'bodies' meld. A human there guardian combine-
Thus is the plot of~ Shugo Rei ~
Guardian spirits is based off all of Hyper-Squads' members, so far all the drawing are by haley. (i need to get the names of everyones guardains)
Haley's guardain is Byakuya who is a red haired angel. she is the last out of the 8 main charictors to awaken her guardian and most of GS is told from her Perspective. byakuya is distant in the beggining.
Becky's guardian is a bunnyrabbit (though specifics are still in progress) haley's best freind and seems to have had her guardian for quite a while... and knows more than she says... (OMG EMO BUNNEH!)
Amber's guardain is like her, multiple personalities, like amber's evil sadistic side, the cunning fox, and her more... 'normal side' a bird (parrot maybe? still under discussion)
Nicky's guardain is random, usually takes the shape of a pixi (NAVI :P) but occasionaly a sheep.. or a giraffe... or a monkey... or whatever the heck she feels like
Claire's guardian is a dragon. though her dragon is quite egotistical.