Name: Scar clan 

Urm. I see why they are called ScarClan. It's ScarClan. One word. Sorry if I seem mean!

Founder: unknown

Why is it unknown? You're making the clan!

Other clans: River clan, Thunder clan, and Blood clan

Why only River and Thunder? And why BloodClan?

Territory: anywhere they can get there paws on

Can you describe it?

Prey: anything they can catch, including deer, dogs and other cats

YOU CANNIBALS

Lol. Nothing wrong with that. That's quite gross, but cool at the same time.

Question: Deer and dogs? No. Stick to more forest-bound prey and smaller than deer.

Present leader: Endstar

What was the Momma thinking when she named Endstar? Was it something like, this kit will be my end?

Present deputy: WolfheartPresent medicine cat: Frostyfoot

Nice names. -foot is an underused suffix, but Wolfheart is kinda overused. No offense, but maybe change his name to like, Wolfspring, Wolfstrike, or Wolfleap.

Backstory: this is a clan of outcasts who have been rejected because of physical deformities. They strive for revenge against the other clans. They ceased believing in Star clan and now believe in Heaven and Hell. They believe that they will all go to heaven and ask who are against them will go straight to Hell. They brainwashed Blood clan into believing in this as well. They are often thought of as just a tale to keep the kits from misbehaving. 

Three words:

What. The. Heck. (I really hope this doesn't sound mean) The deformitites is cool, but what is with the heaven-heck thing? They sound kind of like....a clan made for being evil. That's fine and all, but they seem to just be....

Noticeable traits: they all have some sort of physical deformity and they all have three long, wide scars on their cheeks

Scars....Clan...ScarClan. I see why, but it seems kind of weird.

I give this clan a 4/10. They seem kind of underdevoloped. Sorry Izzyrougeot! I really like your username!