Name: Riversplash. Alright. If a cat is born and raised in the Four/Five Clan settings, they usually don't have River, Sky, Shadow, Thunder or Wind in its name. But everyone has a different writing style, and I'm not saying I don't use them sometimes, but usually only in background characters. 

Past Names: Riverpaw, Riverkit. Cool.

Clan: RiverClan (ik RiverClan and Riversplash ignore that lol) That makes the name a bit more... Unusable. It's like having a person named New York (That was a horrible example, lol. Sorry!) 

Past Clans: non. Alright, she's loyal!

Gender: Female. Cool

 Sexuality: straight. Nice!

 Appearance: a blue-grey tabby she-cat, she has big blue-green eyes. She is not considered plain but is not the prettiest. It's very lacking. What about her fur length, tail size and length, ears, paws, etc? Details are everything in an OC, so a white belly, dapples, folded ear, discoloured toe, etc would make her a ton more interesting. 

Personality: she is very loyal to a fault for her Clan, she dislikes the other Clans always trying to take from their territory and believes they should be exterminated, so usually when she catches a Clan cat stealing or trespassing she attacks them, and if they're dead, she throws them in the river. Also, very lacking. Being able to just kill cats at a whim is near impossible unless she is a massive cat with either nine lives or amazing skills. And her whole personality being hostile and aggressive is off-putting. It's fair that she dislikes other Clans, but she's going a tad bit far. And is there anything else? Brave, short-tempered, thick-headed, quiet, loud, etc.

Mate (If any): none, but she has a liking to a tom named Lakespark. I like his name :) It's very fun to say.

Kits: (If any) none. Alright, cool.

Other Family and Kin: Briarfeather (mother), Whitetail (father), Iceclaw (brother) Whitetail is a very common name, but the other two are very nice. Do they have appearances, though?

Cause of Death or Future Death: drowning. How does she drown? An accident, something heroic, etc. Also, I wouldn't think that a RiverClan cat would drown very easily. 

Rank: (At death): warrior. Okay, normal.

Past Ranks: apprentice, kit. Cool!

Good Traits: loyal, friendly to her own Clan, smart. Seems that way, and they all match up, but she could use some more development. How is she around other cats, her hunting skills, her fighting skills, her reaction to change or conflict, etc? 

Bad Traits: murdery, overreactive. Yeah, I could tell! But again, more development would be great.

Hunting: 8/10

Fighting: 5/10

Swimming: 8/10

Climbing: 5/10

Leadership Skills: 6/10

Reputation: 9/10

A tad bit high. Also, if she randomly kills cats, I think she'd have a lower reputation. Feared, distrusted, considered dangerous, etc.  

Likes: swimming, hunting, RiverClan. Cool, but could use some more details!

Dislikes: other Clans, stealing, boring conversations. Same response as above. 

 Scars/Injuries: a small scar on her back left leg. If she fights so much all the time, I would imagine she'd have more scars and injuries;

Backstory: Riverkit was born to Briarfeather and Whitetail, but her mother died from sickness when she was Riverpaw, and then her father would fawn over Icepaw, barely acknowledging her. She took it in her stride and became a great warrior, Riversplash, and her brother a good fighter, Iceclaw. Sad about her mother. It always hits hard to have a character lose their mother, father or other kin. But this is VERY lacking. What about her friends, her liking of Lakespark, (How did it start and how is their dynamic)  Her reaction to her mother's death, and the start of her hate for the other Clans? Training, growing up, and her relationship with her father. 

Other: none. Okay.

So, this OC is missing a lot and is quite extreme on both sides of the spectrum. Either very over-powerful or very lacking. If she had more development, she would be a great OC, but for now, she's just a bit underwhelming. I give her a 5.5/10. Working on her a bit more is the best advice I can give! Thank you so much for submitting, and sorry if I was a tad harsh, I'm a bit stressed right now.

Bonus: What I think she looks like!