The Mound: Omen of Cthulhu Guide | How Weapon Upgrades Work with the Anvil

Here’s a guide on how to upgrade weapons with the Weapon Upgrade Anvil in The Mound: Omen of Cthulhu.

Game Guide by Jubair Baky on Jul 30, 2026

The Weapon Upgrade Anvil in The Mound: Omen of Cthulhu improves the contract-issued weapons you take into an expedition. The system is easy to miss because the Anvil only shows valid options after a contract has started, and weapons stored inside the cart do not appear in its upgrade menu.

The Mound Omen of Cthulhu Guide How Weapon Upgrades Work with the Anvil

The Weapon Upgrade Anvil is a preparation station aboard the Galleon. Start an Expedition Contract and collect the weapons supplied for that run. You can then interact with the Anvil and spend Tokens on available improvements before leaving for the expedition.

Move the Weapon into Your Inventory

Place the weapon you want to improve directly in your character inventory. The Anvil cannot detect weapons stored inside the cart. If no upgrade option appears, leave the station, retrieve the weapon from the cart, and interact with the Anvil again.

The Mound Omen of Cthulhu Guide Move the Weapon into Your Inventory

Choose the Best Upgrade for the Weapon

Most bladed weapons, bows, crossbows, pistols, and muskets can receive an improvement. Melee upgrades are especially valuable because additional durability helps the weapon survive an entire expedition instead of breaking early. Crossbows can receive faster reload options, while suitable pistols and muskets can be changed from Matchlock to Flintlock so damp weather is less likely to stop them from firing.

The Mound Omen of Cthulhu Guide Choose the Best Upgrade for the Weapon

Remember That Upgrades Are Temporary

Keep the weapon in your inventory, purchase its Anvil upgrade, and repeat the process whenever you begin a new expedition.

Weapon upgrades apply only to the current expedition. They do not permanently improve every future version of that weapon. When you begin another contract, return to the Anvil and upgrade the newly issued equipment again if you want the same advantage.