This is RainbowMustache22 's OC, Bluemist.

Name: Bluemist
That's a pretty name, and it makes sense. And -mist isn't a very common suffix.

Looks: black with frosty teal blue eyes
Hmm... interesting... It sounds pretty, though.

Personality: Brave, loyal, and fierce, but often acts carelessly and speaks without thinking.
The flaws! That's a good thing to have, cuz nobody's perfect! I think this is a good combination between good and bad traits. Nice job! No Mary Sue here!

Gender: she-cat
Man, lots of she-cats.

Backstory: Was once a kittypet named Midnight, but ran away at a young age. Made her was into Windclan camp and was taken prisoner. But Windclan soon realized that she would be a fierce and brave warrior. She was too young to be a warrior, so she was made an apprentice. She soon became Bluemist, warrior of Windclan.
I like how it's not too tragic, because that's used way too often for OCs. I guess I could be kinda guilty of that. Anyways, that's a pretty good backstory!

Extra: Is deaf in one ear.
Did that hold her back at all? Was she discriminated against? Maybe add that to her backstory.

Cause of death: She died while giving birth.
It's Silverstream all over again! But this is a good way to pull at a reader's heartstrings.

Mate: yes (Stoneclaw)
Duh. How else would she have kits?

Kits: yes (4, but Darkkit/paw/blaze was the only survivor)
So the other kits went down with their mother. Tragic.

Clan: WindClan
That's a great Clan. My OC, Cinderflight is half WindClan.

Rank: warrior
She seems noble enough.

Afterlife: StarClan
Makes sense.

Overall rating: 9.9/10
She's awesome! Just maybe add a little more detail to her backstory and she'd be a 10/10!