"His pelt is a snowy white color with scattered dark gray patches; his tail and paws are also a dark gray."
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hm. Perhaps it's possible for a gray cat to have gray paws and a white belly, but if white markings cover the majority of his pelt, I'm thinking his paws would have to be white too.
"Littlestorm is for a Clan and believes that a Clan should reform, and highly recommends"
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If you want to use commas in this list, there should be one after the first "Clan" and only one "and". Otherwise, no commas.
"he believes that if there is to be any leader, it should be him and not anyone else."
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Explain his reasoning behind this in the views.
"Littlestorm was looked down upon and labeled by his father"
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This is by no means mandatory, but I suggest you put this in active rather than passive tense.
"Littlestorm and Whitetail were trained by their father"
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Same here.
"noticed this everyday" <-- two words?
"telling himself that Bleackclaw had no intellect in underestimating him and although that"
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* Bleakclaw
The "that" being Bleakclaw's lack of intellect?
"Overconfident in his own abilities, Littlestorm bounded away from his father and brother towards the rat"
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...bidding them to follow?
"That ‘old’ rat" <-- quotes, not apostrophes
"The mother saw Littlestorm, Bleakclaw, and Whitetail bounding towards her and took them as a threat and got ready to attack."
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She saw and took and got.
By "got ready to attack", do you mean she tensed and crouched?
"Littlestorm saw this and started to skid to a halt," <-- comma splice
"prepared for the blow, but" <-- but he
"That night Bleakclaw died and Whitetail blamed Littlestorm for his death and confronted Littlestorm on his arrogance and stupidity,"
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Lots of ands.
Sure, I'll start to modify it.
andddd I guess I just read the unmodified version, didn't I?