Reckoning is the 22nd and final level of Doom: The Dark Ages. It contains three collectibles. In Doom: The Dark Ages, collectibles consist of toys, codex entries, and weapon skins, found in hidden areas in most levels.
Check out our Doom: The Dark Ages Collectibles Guides Hub for links to guides for every level.
Collectible 1 – Marok Codex Entry
Right at the start of the level, you will drop off a ledge. This is around the corner to the right.
Collectible 2 – The Old One Toy
After clearing the first courtyard, enter the enclosed area to the right of it. There is a secret key lock here that leads to the third collectible, but we will come back for that later. Head past it into a smaller area with a tree portal. Destroy that, complete the encounter, and a gate in the back will open, revealing the collectible.
Secret Key Location
To get the secret key, continue following the main objective through the lower key and up an elevator. Ahead of you will be an upgrade shrine. Turn around, and you will find a secret key and a door leading back to the first courtyard, so you can head back.
Collectible 3 – Ahzark Toy
Head back to the side area off the first courtyard and head through it into a hole on the other side. Below ground, you can grab the collectible.