Kingdom Hearts OC 4: Ran

"Well, it's not like I had anything better to do... so, yes, I am a so-called "guardian of light". I take that duty serious... more or less, even if I have to babysit some knuckleheads doing so. But it's not THAT bad... I do have fun."

First you can see on the left, how she looks like in KINGDOM HEARTS 1 and KINGDOM HEARTS: Chain of Memories.
The one on the right is her in Kingdom Hearts 2 and the floating one is from Kingdom Hearts 3Ds.
 
She has a bad temper and is often in a bad mood, but she is still loyal and you can trust her. Also she is very powerful - you could say she brings death to every enemy. That's her power: death.
She had to protect her world - Hollow Bastion - from Maleficent and the darkness she brought, but in vain... most of the citizen had to flee and then she was destinied to be a guardian of light... but, that's not bad, because she will be able to fight Maleficent while fighting for Hikari and the light. Also she really cares for Leon, wouldn't admit it though -> tsundere.

In Kingdom Hearts 3Ds (Dream Drop Distance) she participates in the Mark of Mastery exam along with Hikari and the others. Her favourite Dream Eaters are Tatsu Steed and Thunderaffe.
After the exam she and her guardians have gained new power and weapons. Now they have to face the dangers ahead.