The average SkyClan cat is brown, black or grey in color, and a tabby, bicolor or both; this combination makes camouflage in the thick jungle-like forest territory much easier than any other pelt type. Pale and/or fiery colors typically come from outsiders, and are discouraged for stealth reasons.
Their builds are light-weight and lean, and they tend to be about average-sized, sometimes smaller.
Their fur is typically very soft and well-kept, regardless of length and texture. There is usually an even mix of long-haired and short-haired cats, and if not then short-hairs make up the norm.
SkyClan eyes are very gentle, cool colors; the most common eye color is green, followed by blue, hazel, and soft honey yellow. Amber, orange, and copper are uncommon and typically come from outsiders. Indigo is also present, and supposedly comes from Branchstar's direct descendants.
SkyClanners have a higher probability of extra toes (polydactyly), curly fur and bobbed tails than the other Clans.
They also have tough, dark grey pawpads and black, grey or brick red noses.
In a perfect world, SkyClan cats would naturally be open-minded and peaceful but highly respectful individuals; and as a group, they would be agreeable when possible, and surprisingly fierce and efficient when not. The best of SkyClan's warriors are very hard to anger, but when it does happen, the instigator regrets it later.
However, it's not a perfect world.
Ever since SkyClan's impromptu revival during Generation II, there has been a very obvious divide between the two “factions” of the Clan: the traditionalists and the reformers. The two sides are in a constant headlock on all issues they care about, with the traditionalists being much more aggressive about their opinions within the Clan, and the reformers being much more open about preaching it to the other “intolerant” Clans. Because of their existence, the SkyClan leader (and often by extension the deputy and medicine cats) are in a constant role as mediator between the sides and always try to find a compromise so both are satisfied whenever they get into a big argument.
Traditionalists greatly value the words and acts of those from the past. They have immense respect for the heroes of their Clan, and look to history not just as a source of inspiration, but also as a source of lessons for how to go forward in the future. They've seen, often first-paw, how well the Warrior Code works for all the Clans to keep them alive and safe during troubling times, so they stand by it verbatim even in the face of outspoken adversity.
In general, traditionalists respect others' privacy on a more regular basis than reformers, believing "to each their own" as long as they follow the StarClan-given law and don't meddle in others' business themselves. Surprisingly, they aren't prejudiced when it comes to sexuality and gender equality, and never really have been - their main concern is with morality of actions, not of relations. There are of course exceptions to both of these, however.
Traditionalists also hold their families dearly, holding loyal to those connected by blood even over their unrelated best friends. Because of this devotion, a treachery within the family hits traditionalists much harder, and it's not unheard of for the head of the family to disown one of its members over something intense enough.
It's not uncommon for traditionalists to be very picky about mating habits; younger traditionalists (of both sexes) are often "protected" during heat seasons, and some parents may be controlling over who they allow to mate with their kits when it's "their time" (specifically, they more often than not prevent them from breeding with reformers or cats outside the Clan). Waiting to bloom until they find and take the perfect mate isn't unheard of either, but it unfortunately leaves many traditionalists prunebuds for their decision. They dislike the breeding pool and the new rules that came with it, believing it's a bastardization of the courtship and reproduction process.
Speaking of family, traditionalists have HUGE ones! Once a traditionalist takes a mate, these cats will have a litter every season-cycle normally (often during spring, but fall may apply too), and "fill the Clan" with their family of kits.
Traditionalists typically get along better with ShadowClan and WindClan cats.
Reformers are very relaxed and liberal when it comes to most rules in the Warrior Code, believing moreso in the "law of the heart" than the time-honored rules of the Clans. If they feel it's necessary, or it's for what they perceive as a greater good, they aren't afraid to bend and break the Code - and face the consequences of it...
Reformers can sometimes be more friendly and compassionate to others than traditionalists from the surface level - this is in part connected to how open-minded they are. Instead of immediately turning to hostility when they meet a strange cat (regardless of where they hail from), expect a reformer to treat them as if they were already friends, and offer support or a helping paw if they need it.
These cats also love their freedoms! They hate feeling judged or micromanaged by others and their rules, and they often believe that all cats should learn to coexist with one another at least a little bit. They think all cats should be treated fairly as an equal, even (and sometimes especially) cats they disagree with, so narrow-minded decisions and quick conclusions are sure to rub them the wrong way in excess.
Reformers typically get along better with ThunderClan and RiverClan cats, as well as those outside the Clans.