For starters you need to think of basic atrabutes for your RPC
Those are things like: Name, Race, And Class
Without at least these three things and RPC can't exist. other things to thing about are physical aperance, and special powers.
I highly advice poeple to search google.com or Yahoo.com for fatasy pictures to base their RPC on. With a picture that you like you can see what you want to look like, so it's easyer to list things like:
Hair Color
Hair Length
Eye Color
Skin Color
Clothing
Height
Weight
Then when it comes to powers think about how you look first. If your RPC is a 4'6" 120lb person, I don't thing you want to be a gladator that uses masive weapons. A character like that seems mor like a mage, or theif. So they need skills like:
Being super sneaky
Lifting thing with their mind
casting magic
knowing Ninja skills
Many RP's will let you mix and match things, so your RPC dosn't have to keep a set list of powers, I have 6 or 7 diferaint versions of my own RPC's at the end of this guide I'll list some as examples
Next is our weapons, like your powers and skills this can also change with each RP you enter, but keeping a small list of fav weapons dosn't hurt.
Guns are easy to use and so most poeple can use them, but fantasy Rp mite require things like swords, so pick a few differaint kinds of weapons to use for roleplays incase you can't your a gun your fav sword is there, or if only rifles can be used you have your fav one on hand.
Last make a simple Bio about your RPC, keep it only a few lines long, and don't use much detail so it's easy to change for the Rp your joining.
After your aviat is loaded out make your own personal profile. I'll leave a copy of what I use to give you an Idea.
Name:
Age:
Race:
Gender:
Hair Color:
Eye Color:
Height:
Weight:
Clothing:
Weapons:
Powers:
Image:
Bio:
Here is two sets of each of my RPC's profiles
Name: Yamato Hekatsue
Age: 20
Race: Werepire
Gender: Male
Hair Color: Silver-white
Eye Color: Sky blue
Height: 6'3" (but can become 10')
Weight: 240Lb (can get over 600 lb)
Clothing: A black cloak and cowl with torn blue jeans
Weapons: None
Powers: Able to change into a beast form that is a mix of were wolf and vampire
Image: None
Bio: Yamato was once a young boy that was bitten by a wolf. After becoming a were-wolf he was out in a dark ally way when he was jumped by a vampire that tried to feed on him. It lift a bite mark that chanced him into both a were-wolf and a vampire.
Name: Yamato Hekatsue
Age: 18
Race: human
Gender: male
Hair Color: Silver
Eye Color: Sky Blue
Height: 6'3
Weight:240 Lb
Clothing: Normaly black T, Jeans, and skeakers
Weapons: PET
Powers: None
Image: None
Bio: Yamato is a high school sudent that plays on the Net alot. His best friend is Neo-X.EXE his Navi. Yamato works alongside Neo-X to fight viruses on the enternet.
Name: Neo-X.EXE
Age: 2
Race: Enternet Navigator (Net Navi)
Gender: Male
Hair Color: Green
Eye Color: red
Height: N/A
Weight: N/A
Clothing: Blue Battle Armor with a green scarf
Weapons: A green energy sword, and buster gun
Powers: A water type navi that can change into a digital beast when threatend.
Image:

Bio: Neo-E.EXE is Yamato Hekatuse's Net Navi, he is a digital program with a smart AI. He thinks and act's on his own but get's his true power from Yamato.
Name: Neo-X
Age: 19
Race: Human
Gender: Male
Hair Color: Blue
Eye Color: Red
Height: 6'3"
Weight: 240LB
Clothing: A black robe
Weapons: A sword shaped like a bat wing
Powers: The sword can rip souls from those it slays, then comand the soul to do what he wants
Image:

Bio: Neo-X is a warrior questing to kill demons and banish their souls to hell.