Iron Chainmail

This is the armor most characters wear through their first serious stretch of exploring, past whatever copper or tin they scraped together and before there is enough silver or gold to move on. The jump in survivability is larger than the numbers suggest, because early enemies land small hits and a few points of defense cancel a good share of each one. Finish all three pieces rather than mixing tiers, since the extra bonus only applies with the complete set on.

Every world generates one of the two ores, and Lead armor is the same rung of the ladder wearing a different name. If your world rolled lead you are not missing out on anything meaningful. Wanting the iron look specifically means visiting someone else's world, which is a lot of effort for a sprite you will replace within an hour of play.

A second helmet fills the same slot. The Ancient Iron Helmet counts toward the set exactly as the normal one does, so it is a pure appearance choice. Skeletons in the Cavern layer drop it occasionally, and Shimmer converts either helmet into the other, so owning one means owning whichever you prefer to look at.

Its design is the original helmet art from the game's earliest patches, kept around after the redesign. The result looks like your character has jammed a bucket over their head, which is most of the reason anyone keeps it in a chest.