[@AutumnFrost] here we go! Could you possibly also add which Clans your cats are in please so I know which ones my important ranks are to go in (so I don't get medicine cats and deputies the wrong way around mostly ahaha)
Hope this is all okay for you, I wanted to be a little bit different with the kinds of prey and the dangers found hence the crocodiles, but if that's too out there for you just let me know and I can take them out XD

[u]About MarshClan[/u]

MarshClan were the native Clan to the territory, established already by the time DawnClan came to be (though not for very long, so the Clans were roughly the same size, though the MarshClan cats knew the territory better). The Clan was named for the vast expanse of marshes that make up the majority of their territory.

MarshClan cats are most well known for being large and incredibly powerful, with a particular talent for swimming, as well as being very sly and cunning. Their coats are sleek and shed water like a duck's feathers, some even say that the cats are more at home in the water than they are on land! 
As the Warrior Code dictates, they take care of one another however MarshClan cats value strength and tradition, so they do not take to outsiders well. They are said to not accept kittypets or loners into their Clan, though rumours have been spread that a rogue who can prove their worth in battle may find place with these cats who have a particular love for battle and contests of strength and wit. 

However, their size and powerful muscles means that they are generally not very agile, therefore they are poor climbers, and don't fare well in places with heavy bushes/tree cover. Most MarshClan cats are also slow and can't run very fast.

[u]Territory and Camp:[/u]
[b][i]The Marshes:[/i][/b]MarshClan's territory is largely open marshland, with peaty, swampy ground and few patches of solid ground. Inexperienced cats who don't know the territory often find their paws slipping out from underneath them and an unexpected dip in the murky water! However, there is enough cover for ambushing prey for those that know how to use it: reed beds and clumps of rushes and other marsh plants, as well as tree roots in some places. Plenty of water-loving herbs like watermint can be found here, but to get the herbs that thrive in drier soils (like catmint and burdock root etc.), the medicine cats must travel right up to the border with DawnClan where the land is less marshy. 
A semicircular clearing can be found near the middle of the marsh, this is where warriors bring their apprentices to train in battle moves.
[b][i]Sick Hollow[/i][/b] MarshClan value their strength above all else, so all cats with contagious sicknesses are moved to a hollow away from the rest of the camp to prevent the sickness spreading through the whole Clan. This hollow has a stream nearby to provide fresh water, and warriors and apprentices regularly visit here when it is empty to make sure there are always clean and fresh nests in case of any sick cats. There is a separate area for the medicine cat to stay in when they're here treating sick cats so they don't catch the sickness, either!
[b][i]Camp(The Grove):[/i][/b] MarshClan's camp is situated in a circular grove of willow trees, on the far side of the marsh. In the center of this grove is the oldest willow tree in the marsh, this is known as the Great Tree. This tree's roots are massive, and span over a considerable distance, creating a space below them where the leader's den can be found; this is where the leader and deputy both make their nests and sleep at night. The leader will jump up into the low hanging branches of the tree to address the Clan and make announcements to the Clan.
The Nursery, Warriors Den, Elder's Den and Apprentice's Den are all also made in the space between the roots of the smaller trees around the edge of camp. 
[b][i]Medicine Cat Clearing[/i][/b]: Past the trees that make up the Elder's Den and the Nursery, the curtain of willow leaves parts into a decently sized clearing of solid ground. It is here that the medicine cat and their apprentice stay, the clearing is right near the stream that feeds into the marshes, and the clearing has a pathway directly out into the Sick Hollow so the medicine cats can move between the two places quickly if needed. Herbs are stored in rock clefts or in hollows in old tree stumps found throughout the clearing.

[u]Prey:[/u]
MarshClan's main source of prey are water birds such as ducks and geese, fish such as pike, and small water rodents. Occasionally, they may find small lizards, snakes or even turtles (though cracking into those pesky shells can be difficult!). More experienced warriors may even work in a tag team to take down some of the dangerous predators that the cats have to watch out for such as otters or even crocodiles!

[u]Brief History and Founding of the Clan:[/u]
The MarshClan cats began as a small family group of cats living in the mountains, who desended distantly from the Tribe of Rushing Water. They were raised on tales of StarClan and the Tribe of Endless Hunting, though they followed StarClan the closest. Eventually, this group grew very large and so a small band of the more adventurous cats, led by the Clan's first leader Pike's Tooth, ventured down the mountain into the territories that MarshClan and DawnClan now occupy. They tried to use all of the territory to themselves at first, but they found that their large builds from living in the mountains were unsuited to the closed forest canopies so they stayed in the marshes mainly, eventually deciding to name their Clan MarshClan after their preferred home. Pike's Tooth eventually became Pikestar and they became a Clan who followed the ways of StarClan very closely. 

They had only very recently settled as an established Clan when Stripedstar and Featherflight arrived to stake claim to the forest territory. Though some cats in the Clan were very angry that this new Clan thought they could take the territory away from them, Pikestar was less opposed to the idea, seeing the reason that MarshClan never hunted there so it wouldn't be a big loss to let them have it. This sparked conflict within MarshClan and with the new neighbours of DawnClan however, leading to quite a viscious war during which many of the cats who had led the rebellion died. This is how the Dark Forest came to be in these new territories, and while the Clans have lived relatively peacefully side-by-side for generations, a new leader is on the rise in MarshClan, a leader not chosen by StarClan but instead put into power by the vengeful, bloodthirsty cats of the Dark Forest....

Will they succeed in taking over the territories and eliminating StarClan and the belief system forever, or can the terrible plot be exposed before it's too late?