Difficulty

Terraria asks you to choose a difficulty twice, and the two choices control different halves of the game. Character difficulty is set when you make a character, and it only governs what a death costs you. World difficulty is set when you generate a world, and it governs how hard everything hits and what it drops. Neither can be edited afterward. A Mediumcore character in a Classic world fights ordinary enemies under a harsh death penalty, while a Classic character in a Master world fights monsters with triple health and loses almost nothing when one connects. Journey is the exception to the pairing: Journey characters can only enter Journey worlds and Journey worlds only accept Journey characters, so picking it in one menu commits you in the other.

Higher character difficulty unlocks nothing. There is no exclusive drop and no reward tied to it, outside one special-seed achievement. It exists to make failure hurt, so pick it because you want the pressure rather than because you expect a payout.

• Classic scatters a portion of your coins and respawns you at your spawn point. Everything else stays put. In Expert or above the loose coins are fair game for enemies, so a death in a crowded room can cost more than the timer suggests.
• Mediumcore empties the entire inventory onto the floor, ammo and coins included. It is all recoverable, but recovery means walking back unarmed to wherever you died, which is a very different proposition in the Underworld than in your yard.
• Hardcore deletes the character file. Items sitting in chests survive because they belong to the world, but anything inside a Piggy Bank or Void Vault goes with the character.

A dead Hardcore character becomes a ghost that keeps watching the world. Ghosts fly, pass through blocks and can still chat in multiplayer, but they cannot pick anything up or load a world of their own. It doubles as a free exploration tool since nothing can hurt you and terrain no longer exists, though ghosts emit no light and caves stay black. Every town NPC in a world that has hosted a Hardcore death starts dropping Tombstones, and enough of them in one spot turn the area into a Graveyard. In multiplayer, anyone can collect your dropped gear, and nothing stops you rejoining on a fresh character to pick up your own pile.

One seed combination changes the rules entirely. With Celebration Mk 10 and The Constant both active and For the Worthy switched off, a Hardcore death permanently removes 60 maximum health instead of ending the run, and only kills the character for good once that subtraction reaches zero. See the secret seeds list for the exact world names.

World difficulty is where the trade sits. Expert and Master keep the same enemy roster but rewrite stats and several attack patterns, and in exchange loot rolls more often and bosses hand over Treasure Bags holding items that exist nowhere else. Master adds a further health and damage tax on top of Expert, a guaranteed relic per boss, a chance at a themed pet or mount, and an extra accessory slot. Journey sits below Classic and gives you a slider instead of a fixed setting, so it can imitate any of the other three on demand. A Master world running the For the Worthy seed is what people mean by Legendary.

The third difficulty step is not a menu at all. Killing the Wall of Flesh converts the world permanently: new ore tiers appear, the Hallow generates alongside your evil biome, and enemy tables everywhere shift up a bracket. Every world reaches it eventually and there is no way back. In Expert and Master, weaker enemies also collect a scaling bonus at that moment and another one after Plantera dies, which is why a Zombie in a late-game world is not the zombie you met on night one.

• For the Expert-only gear without a punishing death loop, run a Classic character in an Expert world. The Demon Heart and its permanent sixth accessory slot are worth the trip on their own.
• Mediumcore only pays off if you enjoy the tension. Park a chest near spawn holding your previous set of gear so a bad death costs an hour rather than a run.
• Hardcore rewards patience over reflexes. Build an arena before every boss, keep a Magic Mirror on the hotbar, and remember that a few items generate once per world and cannot be farmed back.
• Master is a gear check more than a skill check in the opening hours, because defense counts for everything there and you begin with none of it.