Biome Chests

Biome Chests are Hardmode, post-Plantera Chests found within the Dungeon. Each contains one specific rare, powerful weapon, in addition to other miscellaneous items. While Biome Chests are placed during world creation, they are initially locked and can only be opened with an appropriate Biome Key, which will only become available in Hardmode, and only after Plantera has been defeated.

Only four Biome Chests (one of each type) will spawn in a particular world. Each represents a biome found in the current world. There are five types of Biome Chests in total, though a world will only contain one of the Crimson or Corruption variant, depending on which of those biomes the world contains.

To open a Biome Chest:


 * Obtain the appropriate Biome Key Mold by killing enemies within the respective biome.
 * Defeat each Mechanical Boss to obtain 5 each of the Souls of Fright, Might, and Sight.
 * Kill Plantera to obtain a Temple Key.
 * Craft the Biome Key from the Biome Key Mold, Souls, and Temple Key
 * Return to the Dungeon and find the appropriate Chest for the Key you crafted.

Biome Chest progression
The chests also contain common items depending on the height they were found:


 * Surface
 * Underground
 * Caverns

Tips

 * Biome Key Mold drops are incredibly rare (1/2500 chance of a key mold dropping from a defeated enemy in a biome). You'll probably need to defeat many thousands: 1732 to have a 50% chance, 3000 for 70%, and 5750 for 90%. With the right equipment and some time, you can set up a mold farm or grinder in the biome to get there sooner.
 * To find what chance there is for at least one to drop for a given number of mobs, use the equation 1-(1-([drop chance]))^([number of mobs]). To find how many mobs are needed to obtain a certain percent chance it has dropped at least once, use ln(1-[%chance in decimal (70% = .7 etc...)])/ln(1-[drop chance]).