In most Soulslikes, you can upgrade your weapons for extra damage. The same goes for Another Crab's Treasure, where you can upgrade your primary melee weapon: your trusty rusty fork.
Another Treasure of the Crab | All Stainless Steel Relics Locations | Make It Shine Achievements/Trophies Guide
To upgrade your fork in Another Crab's Treasure, you'll need to travel to a specific location in the game. You'll first need to defeat the Duchess Magista, but once you reach the beautiful city of New Carcinia, you'll be given the opportunity to level up your melee weapon.
New Carcinia has two levels: the Upper and Lower Crusts. To upgrade your weapon in Another Crab's Treasure, you'll need to go to the Lower Crust and talk to Hammerhead. The location is on the map above. He can be found right next to the Moon Snail Shell in the middle of the undercity. Hammerhead is one of the four NPCs you need to talk to before you can progress the story, so you'll likely encounter him naturally as you play.
After talking to him, select the Upgrade Fork option. Whenever you want to upgrade your fork in Another Crab's Treasure, you'll need to transfer a rare item called a Stainless Relic (pun intended). And with each upgrade, you'll need an additional relic. The first upgrade requires one relic, the second two, and so on.
