Whilst we have the map created (Which is being made via this information here) and the plot is fully fleshed out, here is some details on the territory the Roleplay will take place within, as well as the clans we will expect to see.
Firstly, as you may have already known, there are three clans in this RP, along with a new territory. I'll try to get as much information as I can that should paint the perfect picture for you to create a map, and I'll add some background information inwards from there just so you can get an early glimpse at some of the lore.
As for the entire territory, the lands are somewhat evenly matched. The most prominent of the territory are the three separate lands, which are known as the Layered Lands to most of the cats. Though the "layers" are rather unbalanced in their proportion, they still are what separates the three clans apart significantly. On the Western Side of the territory sits the Highstones of Sundown, where the setting sun is not visible due to its placing. This "Mountain" (Loose term, as it isn't of any extreme size but rather a mountain for the cats themselves) has a series of tunnels mostly narrow and only able to fit about three cats wide in most of its passages. These caves have areas where light pours in, such as holes and gaps in the cave's ceilings, which sometimes resolves in flooding towards the deeper caves. Most of the caves are relatively dark, which is what accommodates its clan well. Some "Mountain Goats" of the area make for some vicious combatants to disturbing clans.
In the centre valley, we have the Forest. The forest is what houses the second of the clans, and by far the largest. The trees are mostly compacted together and there are not many open areas within it. The biggest and most notable area that's open is only the camp of OakClan and an old spacing from where a previous clan may have lived. The prey itself is mostly the usual, moles, hares and mice, the usual prey to be expected. The forest covers the most amount of area of the land, separating the East from the West, where the Highstones are the only higher level in the territory.
On the Eastern side, you have the Marshlands. Previously a smaller forest located on a closer-to-sea-level valley, the erosion of a nearby river meant that the lowest level in the territory would find itself being constantly flooded. Over the years the clans remained in the area, they learned to adapt and shift to its accustoms, as the water level raised on minor scales. Most areas of the Marshlands, the nickname otherwise used in place of the Sunken Forest, have water-levels up to the neck or tuft, whilst certain parts of the less-dense forest are littered with uprooted trees to use for shelter, raised lands and tiny hills that look like tiny islands amongst the water. The camp its clan houses is very secure, but overtime has seen itself using fallen logs that have floated ashore the camp's "Island hill" to be used as shelters.
Now for the clans, it's very simple. Firstly, in the Highstones of Sundown live NarrowClan. Whilst their original name was something along the lines of TunnelClan, they had their name changed by the clanmates nicknaming themselves after the early difficulties they had with their narrow tunnel home. The newest of the three clans, NarrowClan is one of the more dangerous of lives, as those unaware of the highstone's depths can easily fall into any unknown region of the caves, or it's "Under-Lake". The clan is mostly quite compact, and has two areas for its 'camp'. Two openings inside the cave are present, one with a hole in the ceiling for easier visual communication and a second further down as a fallback camp. The fallback camp resides nicely with their ideals of defence and holding any ground they can get from tribes or other clans. Whilst their territory is not only restricted to the tunnels, they have areas at the bottom of the highstones that link with the edge of the Forest, usually where the hunting is. Due to the moderately painful climb towards the clan's tunnel entrance, invading the clan can be quite a tedious struggle.
Secondly we have OakClan, the brawn of the forest. Being the middle-layer clan, above the water level spilt from the eroding river, they are mostly where a vast majority of the prey resides. Well fed and well stocked, these cats are very avid tree climbers and can be the masters of ambushing due to their dense homeground. As for their backstory, OakClan actually consist of two separate clans that merged together when the leaders of either clan became mates and arranged for a prosperous life. And a prosperous life was what they got, as the clan grew to extensive size and had the numbers to oppose any other clan. Whilst the other clans balanced out defence and tactics, the numbers that OakClan had could balance out the different offensive ways each clan could deal with war.
Finally, there's ReedClan, the clan we will be taking place within. Within the flooded forest's lands, and residing on one of the many small raised land patches that make out tiny islands, this Clan is well organised and well prepared for worse-case scenarios of natural danger. Utilising shelters such as large bushes, hollowed out logs and small burrows, these cats have a widespread amount of territory for them to protect, most of which is already protected by the waters. There's aren't any dangers that lurk within the waters, but the cats have the speciality to traverse the toppled trees, swim through the deeper ends and act on both an offensive and defensive advantage. This clan uses tactics and critical thinking to raise the greater leaders and deputies, allowing for elements of reorganisation, extensive planning and careful operational creation to take place whenever a threat is looming around. They most feast on the fish that swim from the exposed banks of the river, as well as several amphibians local to the area and mice that live on the tiny "Islands."