Name: Mapletail. Okay! Tail is a pretty generic suffix, but if it has reasoning, (Which in this case, it does,) It's fine. 

Name reasoning: Maple for his bright spotted pelt that looks like a maple tree in autumn, Tail for his long fluffy tail. Makes sense. 

Past names: Maplekit-Maplepaw/Maplecrash(by Amberflight) So, Maplecrash is like a little pet name from his mate? That's sweet. 

Clan: SmokeClan (was founded by Smokefur, later Smokestar. Situated on the bank of a river, it has forest and meadow on its territory. Clan territory is nearest to the Moon Willow, but furthest to the Glade of Gatherings) Alright! 

Gender: male. Cool.

Sexuality: hetero. Not much to say here! 

Appearance: a muscled tom with long spotted fur with brown, orange and golden spots, a white chest and belly, big and bright orange eyes, a fluffy long tail and sharp claws. A few more details, like certain prominent markings, ears, scars, etc could be nice, but this is a pretty good basic description! 

Personality: he has an independent and tough exterior and he rarely opens real himself in front of other cats. He loves to learn something new, to gain new experience. Some more details would be nice here too. Is he quiet? Curious? Maybe introverted? Details are important. 

Mentor: Silverleaf- fluffy white-grey she-cat with long whiskers and beautiful bright blue eyes. Okay.

Apprentice: Lightmist(in future)- light grey, almost white, she-cat with long legs and yellow eyes. Cool!

Mate: Amberflight- small she-cat with light orange fluffy fur, torn ears and blue eyes. Alright.

Kits: Foxpaw/Foxwing(daughter)-small orange she-cat with a white muzzle, neck and belly, strong paws and orange eyes. I like her description! 

Amberkit/Amberfern(son)- light orange fluffy tom with amber eyes. A cat having the same name as its parent is a bit strange, especially because that parent is still alive. If his mother had died, and he'd been named after her, that's fine, but it's confusing. 

Sprucekit/Sprucetail(son)- brown tom with a long tail and bright green eyes. Okay. 

Berrykit/Berryblaze(son)- orange tom with white spots and blue eyes. Alrighty. 

Bearkit/Bearfeather(son)- brown tom with golden spots and amber eyes. Wow, Mapletail has a lot of kits! 

Other Family and Kin:

Father: Brookface- grey tom with white spots on short fur, long whiskers and bright yellow eyes. I love the suffix "face"! It's so goofy.

Mother: Deermoon- small long-furred golden brown she-cat with a beige belly and paws, white dots on her back and bright dark amber eyes. Alright.

Half-sister: Crane (later Cranedance)-small short-furred gray cat with white, light grey and dark grey spots and light green eyes. Alright! 

Grandmother: Mallowspark- beautiful orange-white she-cat with thin legs and shiny orange eyes. Okay! 

Grandmother: Leafdance- very small and thin, pale tortoiseshell and white cat with grey and light orange spots, green eyes and soft fur. I like that you've put both sets of grandparents!

Grandfather: Elderthorn- dark brown striped tom with long fur and yellowish green eyes. Okay, cool. 

Grandfather: Lionstep- golden brown tom with very sharp claws, small ears and big yellowish-green eyes. His name suits him. 

Uncle: Yewstar- big muscled tortoiseshell tom with big ears, orange eyes, long, a little bit matted fur and fluffy tail. I love the amount of detail with this family! Both sets of grandparents, both sets of aunts and uncles, step-siblings, etc. 

Uncle: Pinewhisker- small brown striped tom with short soft fur, small ears and dark green eyes. Cool! 

Uncle: Bearshade- big brown tom with strong shoulders, small ears and green eyes. I like the trend of animal names. Lion, Lynx, Bear, Deer, etc.

Uncle: Lynxclaw- big muscled tortoiseshell tom with soft short fur, fluffy tail and green eyes. Not much to say here! 

Cause of future death: will break his neck from falling from the tree. Poor guy! 

Rank(at death): warrior. Alright. 

Past ranks: kit-apprentice. Normal. 

Good traits: He likes to spend time with kits, he knows many stories and games and he easily entertains them. He is very adventurous and curious, he likes to wander, to have friends in other Clans, to learn some new battle technics. Cool! 

Bad traits: Mapletail sometimes not watch over what he says, and he can say inappropriate words or things in front of kits or apprentices. He often complains about something and other warriors joke that Mapletail should live in the elders' den. He can not obey the head of the patrol and quarrel with border patrols. I relate to accidentally saying inappropriate things in front of children- sometimes I'll accidentally swear and they'll stare at me like I just told them the world was ending, lmao. 

Hunting:8/10

Fighting:7/10

Swimming:2/10

Climbing:5/10

Leadership skills:7/10 

Reputation:7.5/10.

A tad bit high, but not too bad. 

Likes: Attending gatherings, his friends Leaftail and Clouddawn from FireClan, the sound of crunching leaves under his paws, the taste of pigeon. Fair enough! 

Dislikes: when someone interrupts him, spiders, budgers, to jump from the trees during or after hunting on trees (He is really ungraceful while landing and was jokingly named Maplecrash by Amberflight) Cool! 

Scars/injuries: has a torn ear and scar on his right leg from a fight with Rabbitleg. Ah. 

Backstory: Maplekit was born to Brookface and Deermoon as the only kit. In his kittenhood, he used to play a lot with Amberkit, Swiftkit and Birdkit. After the death of Birdkit from Greencough Maplekit refused to go outside. For how long? How close was he to Birdkit? 

At six moons he became an apprentice with mentor Silverleaf. During his apprentice-hood, his father died from an attack by a badger, and his uncle Yewstar became his fatherly figure. His clanmate, Amberpaw, became his friend and helped him to cope with his father's death and thoughts about taking revenge and killing that certain badger that had taken life from his father. When Maplepaw found out that Rabbitpaw from Fire Clan was crushing on Amberpaw, he decided to talk with him and give him advance to search for a mate in Fire Clan. That conversation became a fight and both apprentices were punished, but Maplepaw was excited to find out that Rabbitpaw was not looking at Amberpaw anymore. Okay! The uncle becoming a fatherly figure is a neat detail. 

Soon after becoming warriors, Mapletail and Amberflight became a couple. They had two litters of kits. Soon after his second litter was born, Mapletail became a mentor of Lightpaw, the daughter of the Clan's leader Rosestar. While mentoring he and Lightpaw found a wounded loner and asked medicine cat Thymefall to help her. While talking Mapletail and the loner Crane found out that they share the same father. Crane decided to stay in the clan and become a warrior and soon she got her warrior name Cranedance. That's cool! Do they know who Cranedance's mother is? And above you said Yewstar, as in the leader, but here it says that Rosestar is the leader; Did Yewstar die? Also, how far apart were the two litters of kits? 

Mapletail had Greencough and was very afraid that he would die like Birdkit, but deep inside he wanted to see his kittyhood friend. Next moon as his apprentice Lightpaw became a warrior Lightmist while hunting on trees Mapletail took an inaccurate jump, fell from a tree and broke his neck. That seems like a pretty underwhelming death; there's no real purpose to it. When you kill off a character, there has to be a purpose. 

Overall, Mapletail is a pretty good OC! His backstory could use a bit of work, but for now, he's okay! 7/10.

Bonus: What I think he looks like: