The Kar'Thul Marshes is the sixteenth chapter in Doom: The Dark Ages, featuring an open-world map where the Doom Slayer continues the quest to find Thira. The map contains 5 Secret Areas, 188 Gold, 1 Ruby, 1 Wraithstone, 2 Demonic Essences (Armor & Ammo), and 2 Collectibles (a codex page and a toy).
The Slayer's search for Thira continues.

Starting Point x1, Secret Areas x5, Codex Entry x1, Collectible Toy x1, Weapon Skin x1, Life Sigils x2, Soul Sphere x1, Sentinel Shrine x1, Demonic Essences x2, Wraithstone x1, Ruby x1, Gold x188, Switches x3, Metal Lock x1, Wolf Statues x5, Demonic Leaders x2, Encounter (Large) x1, Encounters (Small) x5, Mission Objectives x3, Points of No Return x2
The following legend of The Kar'Thul Marshes interactive game map defines the points of interest / markers displayed on the map. Each marker corresponds to a specific element to facilitate efficient navigation and interaction with the map.
Starting Points are specific locations where players begin each of the game's 22 chapters. These points serve as the initial spawn or entry point for the Doom Slayer.
Secret Areas are hidden level sections containing collectibles like Codex Entries, Toys, Life Sigils, Gold, or Weapon Skins. To reach them, you will have to find hidden paths, obtain the necessary key, and so on.
Codex Entries are collectible items that provide lore and background information about the game's world, characters, enemies, weapons, and story. They are typically found in the Secret Areas or hidden locations within levels, rewarding exploration.
Collectible Toys, also referred as "Dolls," are hidden items scattered throughout the game's levels, typically found in the Secret Areas or in hard-to-reach spots. These toys are small, detailed models of characters or enemies from the game, serving as collectibles that reward exploration.
Skins are cosmetic items that alter the appearance of the Doom Slayer's weapons, offering no gameplay advantages. They are collectibles often found in the Secret Areas, hidden paths, or as rewards for completing specific challenges or levels.
Life Sigils are collectible power-ups that function as extra lives, allowing the Doom Slayer to instantly recover upon death without losing progress or restarting at a checkpoint. They are typically found in the Secret Areas or hidden locations.
Soul Spheres function as health and armor boosters. Picking up a Soul Sphere refills the player's health and armor to their maximum values.
Sentinel Shrines are special locations in levels where players upgrade weapons, shield, and melee abilities. Players use Gold, Rubies, and Wraithstones to unlock enhancements that boost combat effectiveness.
Demonic Essences are collectible resources obtained by defeating specific enemies called Leaders. These powerful enemies drop Demonic Essences when executed, which permanently upgrade the Doom Slayer's Health, Armor, or Ammo capacity.
Wraithstones are the rarest currency in the game. They can usually be found in secret locations, accessible after obtaining the appropriate key or completing specific tasks. They are used at Sentinel Shrines to unlock advanced upgrades for your arsenal.
Rubies are rarer, often hidden in tough-to-reach spots or gained from difficult encounters resources used to unlock higher-tier upgrades at Sentinel Shrines.
Gold chests, stacks, and bars provide gold, a base currency you gather to purchase most upgrades at Sentinel Shrines.
Various types of switches, levers, valves, and similar mechanisms that need to be activated to open a passage, remove a barrier blocking a path, etc.
Metal Locks that can be shattered by hurling a Shield Saw at them, which usually allows you to clear a blocked path. They can only be targeted when approached from the proper side.
Wolf Statues are glowing red statues, environmental puzzles in specific chapters. Destroy them using the Shield Saw to remove a forcefield around rewards like Rubies or Wraithstones. Completing these puzzles may also unlock mission challenges and cosmetic rewards.
Demonic Leaders are formidable demons in Doom: The Dark Ages. Defeating them rewards players with a Demonic Essence, granting a permanent boost to health, armor, or ammo capacity.
Encounters refer to combat scenarios where the Doom Slayer faces large groups of demons or specific enemies in the game's levels. These are intense, action-packed battles that test players' combat skills, often requiring strategic use of weapons, shields, and movement.
Encounters refer to combat scenarios where the Doom Slayer faces groups of demons in the game's levels. These are intense, action-packed battles that test players' combat skills, often requiring strategic use of weapons, shields, and movement.
Places related to the main story in a particular chapter, etc.
Points of No Return are specific locations in chapters where, once crossed, the Doom Slayer cannot backtrack to previous areas without restarting the chapter or reloading a checkpoint.