The chestplate in Iron Soul is usually unlocked by crafting it with the right ore/materials , not by a separate “unlock” menu. Recent community guides point to witherite as the main material for stronger chestplates, with one guide saying a chestplate like Shadow Throne takes about 21 witherite to craft, and lighter armor is cheaper if you want faster early progression.

How it works

  • Go to the Forge/crafting area in-game.
  • Collect the required ore, especially witherite for better armor.
  • Craft the chestplate recipe you want once you have enough materials.
  • If you are missing the recipe, it may be tied to game progress, dungeon drops, or a specific armor tier.

Fastest way to get it

  • Farm OC hell mode trial or similar dungeon content for better ore drops.
  • Use the materials to craft armor repeatedly until you get the chestplate tier you want.
  • For cheaper progress, some players recommend making light armor first because it is faster and easier to mass-craft.

What players are saying

A recent Iron Soul FAQ video says the best armor ore is rotton/rotten lotus and that witherite is the main material for strong armor crafts, including chestplates. That same discussion says chestplate crafting is part of the normal forge progression rather than a hidden unlock quest.

In one line

To unlock the chestplate in Iron Soul, farm the needed ore and craft it at the forge , with witherite-based recipes being the most common path for stronger chestplates.

If you want, I can turn this into a step-by-step chestplate farming route for Iron Soul.