Vanilla changes

The Calamity Mod changes several aspects and details regarding vanilla Terraria content, ranging from the order in which bosses can be fought in to which items are sold by NPCs.

The Calamity Mod also changes multiple vanilla item recipes. To see those, click here.

The changes listed here occur as long as the Calamity Mod is installed, and are not restricted to any modded difficulty modes. See the Revengeance Mode or Death Mode pages for changes that occur exclusively within those modes.

Starting
In every new player's inventory, there will be a Starter Bag, the Iron Heart, and the Revengeance. The Starter Bag contains numerous useful items and can be opened to help speed up the beginning of the game. The Iron Heart and Revengeance items, only usable in Expert Mode, will toggle their respective difficulty modes when used. Inside the Starter Bag are also the Death and Defiled Rune items, which each activate more challenging yet rewarding difficulty modes that can be toggled on and off, but only while Revengeance Mode is active.

Progression
The Calamity Mod makes heavy adjustments to the progression of Hardmode, removing many restrictions on the order in which bosses must be fought. In vanilla Terraria, many Hardmode bosses require other bosses to be defeated before they can be fought, creating a linear sequence of progression. Calamity introduces several means through which bosses can be fought "out of order", which greatly increases the player's choices and freedom during Hardmode.


 * The Steampunker NPC is now available as soon as Hardmode begins, removing the prerequisite of having to defeat a Mechanical Boss.
 * Life Fruits are also available from the start of Hardmode, without the need of defeating a Mechanical Boss.
 * Plantera's Bulbs can spawn before mechanical bosses are defeated. The Portabulb is also available to manually summon the boss.
 * The Temple Key and a variant of the Lihzahrd Power Cell are now craftable with early-Hardmode materials, meaning that Plantera does not need to be defeated in order to enter the Jungle Temple and fight the Golem.
 * Using an Eidolon Tablet, dropped by the Eidolists found in the Dungeon and the Abyss, will summon the Lunatic Cultist regardless of whether or not the Golem has been defeated. Eidolists begin spawning as soon as Hardmode begins, meaning that the Lunatic Cultist, the proceeding Lunar Events, and the Moon Lord can all be fought at any time after defeating the Wall of Flesh.

World Generation

 * The Jungle Temple's generation has been changed to guarantee a large arena to fight the Golem in.

Treasure
The mod generates many structures containing certain items normally exclusive to different points of progression, including hardmode.
 * Evil Islands will be comprised of the evil biome opposite to the one chosen upon world generation. The corresponding Biome Chests are on these islands as well.
 * Some planetoids contain Enchanted Sword Shrines.
 * The Ice Bio-center Lab generates with either the Arctic Diving Gear, Blizzard in a Balloon or the Frozen Turtle Shell.
 * The chests in the Brimstone Crag contain several treasures:
 * Loot previously exclusive to the Shadow Chests scattered across The Underworld, making them easier to obtain.
 * The Magma Stone, Obsidian Rose, and the Philosopher's Stone, which were exclusively enemy drops.

Items sold by Town NPCs
Certain items with different requirements in progression are made alternatively available through Town NPCs. Clentaminator solutions also cost, as opposed to the original price of.

Damage

 * Crystal Bullet shards will deal 40% less damage. The damage penalty takes the gun's base damage into account.
 * Hallowed Stars from Holy Arrows will deal 30% less damage. The damage penalty takes the bow's base damage into account.
 * Chlorophyte Bullets will deal 20% less damage. The damage penalty takes the gun's base damage into account.
 * The damaging orbs from the Spectre armor set bonus will deal 30% less damage.

Defense and DR

 * Player damage reduction now scales with diminishing returns, with all DR reducing effects (such as Marked and Cursed Inferno) being calculated after it has been scaled.
 * The scaling formula is: 1 - 1&frasl;(1 + dr)
 * The Worm Scarf only provides a 10% damage reduction instead of 17%. This brings it in line with the Bloody Worm Scarf.
 * The Frozen Turtle Shell only provides a 15% damage reduction when under 50% health instead of 25%.

Difficulty Indicator
The Difficulty Indicator is a UI element that is located to the left side of the player's minimap while the player's inventory is open. It holds three rune slots that help to indicate which Calamity Mod world difficulties are currently enabled:
 * If the Difficulty Indicator is empty, it means the world does not have any Calamity Mod difficulties enabled.
 * If the top rune is active, it indicates that either Revengeance Mode or Death Mode is currently active. The Revengeance Mode icon is a red skull while the Death Mode icon is a red pentagram.
 * If the bottom-left rune is active, it indicates that the Defiled Rune is currently active.
 * If the bottom-right rune is active, it indicates that Armageddon is currently active.

Minions

 * Minions are changed to automatically adjust their damage whenever the player's equipment is changed, no longer needing to be re-summoned in order to take effect.
 * All attacks labeled as summon will deal 50% less damage if the player is holding a weapon belonging to a different class.
 * Summon attacks will deal 10% greater damage while holding a summon weapon.
 * This effect will not trigger when holding a Tool or Classless weapon.

Modifiers

 * Defensive accessory modifiers now also increase damage reduction and gain more defense in Hardmode and Post-Moon Lord, with rarer defense modifiers granting a larger bonus.
 * Hard provides 0.25% damage reduction; and increases to 2 defense in Hardmode and 3 defense in Post-Moon Lord instead of 1.
 * Guarding provides 0.5% damage reduction; and increases to 3 defense in Hardmode and 4 defense in Post-Moon Lord instead of 2.
 * Armored provides 0.75% damage reduction; and increases to 4 defense in Hardmode and 6 defense in Post-Moon Lord instead of 3.
 * Warding provides 1% damage reduction; and increases to 6 defense in Hardmode and 8 defense in Post-Moon Lord instead of 4.
 * Critical strike chance accessory modifiers are nerfed, with the Precise modifier now granting a 1% bonus and the Lucky modifier now granting a 3% bonus.

Lethal Lava

 * Standing in lava will inflict the Lethal Lava Burn debuff.
 * The Obsidian Skin Potion provides temporary immunity to lava burn and reduces lethal lava burn damage.
 * The Obsidian Rose greatly reduces lethal lava burn damage.
 * The temporary immunity to lava given by the Lava Charm and its upgrades provides immunity to lava burn while active.
 * This can be removed through editing the configuration options. However it is always active in Death Mode, regardless of this option.

Enemies & Bosses

 * Debuff times in Expert Mode are no longer doubled. This can be reverted through editing the Configuration options.
 * In Expert Mode, enemies will not spawn in towns. This can be reverted via configuration options.
 * When a boss is alive, the Boss Zen debuff's effects are applied upon the player.
 * While in Pre-Hardmode, the spawnrate of Voodoo Demons is increased.
 * At the beginning of Hardmode, before the player has summoned or fought any boss, all enemies are weaker. In Normal mode, all enemies have 20% less HP and attack damage. In Expert mode, they have 40% less HP and attack damage to compensate for their higher original stats.
 * Tomb Crawler health is nerfed by 40% while in Pre-Hardmode.
 * Dungeon Guardian health is nerfed by 90%.
 * The Eater of Worlds and The Destroyer take only 1% damage for a few seconds after spawning.
 * The Destroyer's segments take reduced damage from piercing projectiles. Piercing projectile damage is halved.
 * The nail projectiles from the Nailhead enemy have their damage nerfed by 25%.
 * Golem enrages if it is fought outside the Jungle Temple.
 * The Martian Saucer no longer counts as a boss for the purposes of Adrenaline, Armageddon, or Boss Zen effects.
 * Duke Fishron's Sharknadoes and Cthulhunadoes take a second before dealing damage.
 * Lunatic Cultist's health in Normal Mode and Expert Mode is increased (32,000 to 38,400 / ).
 * Multiplayer scaling of bosses' health is decreased. Calamity takes the boss's health on multiplayer and multiplies it by a scalar to reduce it.
 * For two players, 82% of health is contributed per player, totaling 164% of base (singleplayer) health.
 * For three players, 72% of health is contributed per player, totaling 216% of base health.
 * For four players, 64% of health is contributed per player, totaling 256% of base health.
 * For five players, 57% of health is contributed per player, totaling 285% of base health.
 * For six players, 52% of health is contributed per player, totaling 312% of base health.
 * For seven or more players, health is multiplied by 47% of health is contributed per player, totaling 329% of base health with seven players.
 * The Dungeon Cultists are set to respawn faster.
 * The Celestial Pillars require enemies to be defeated in Expert Mode instead of 150. This can be removed through editing the configuration options.
 * Some bosses drop differing amounts of money.
 * The Queen Bee drops 5 Gold Coins.
 * Skeletron drops 7 Gold Coins.
 * Duke Fishron and the Lunatic Cultist drop 25 Gold Coins.
 * The Moon Lord drops 30 Gold Coins.
 * Caster AI enemies deal no contact damage.
 * Green Jellyfish can now spawn during Pre-Hardmode. However, their base damage is reduced to 40 and their defense is reduced to 4.
 * Complementing this, Blue Jellyfish can now spawn during Hardmode.
 * Several vanilla enemies and bosses are now immune to Webbed:

Environment

 * In the Snow and Ice biomes in Expert mode, the player is inflicted with Frozen Lungs when submerged in water, draining their breath much faster; however, the water no longer inflicts Chilled on the player. This feature can also be reverted though editing the configuration options.
 * Boulder traps deal less damage, but inflict Broken Armor for 10 seconds on hit.
 * Explosive traps deal much less damage, but inflict On Fire! for 10 seconds.

Vanilla Boss Additions
The Calamity Mod changes Vanilla Boss AI in both Revengeance Mode and Death Mode. The changes are summarised below.

Armor

 * Pre-Hardmode ore armors now increase mining speed, with greater bonuses for more expensive materials. The alternate ores provide a 5% weaker buff compared to their normal counterparts, due to providing extra defense.
 * Copper armor's set bonus now increases mining speed by 15%.
 * Tin armor's set bonus now increases mining speed by 10%.
 * Iron armor's set bonus now increases mining speed by 25%.
 * Lead armor's set bonus now increases mining speed by 20%.
 * Silver armor's set bonus now increases mining speed by 35%.
 * Tungsten armor's set bonus now increases mining speed by 30%.
 * Gold armor's set bonus now increases mining speed by 45%.
 * Platinum armor's set bonus now increases mining speed by 40%.
 * Some previously classless armors have been modified to grant bonuses to the rogue class, among other changes.
 * Gladiator armor:
 * Helmet now grants 3 defense (instead of 2) and increases rogue damage by 3%.
 * Breastplate now grants 5 defense (instead of 3) and increases rogue crit chance by 3%.
 * Leggings now grant 4 defense (instead of 2) and increase rogue projectile velocity by 3%.
 * When a full set is equipped, it grants the player 3 defense and 5% increased rogue damage and 10% increased rogue velocity.
 * Obsidian armor:
 * Outlaw Hat now increases rogue damage by 3%.
 * Longcoat now increases rogue crit chance by 3%.
 * Pants now increase rogue projectile velocity by 3%.
 * When a full set is equipped, it grants the player 2 defense, 5% increased rogue damage and crit chance, the Lava Charm effect for 3 seconds, and the Obsidian Skull effect.
 * Hallowed armor:
 * Plate Mail now grants 18 defense (instead of 15).
 * Greaves now grant 13 defense (instead of 11).
 * Total defense granted is now 36/55/40 (instead of 31/50/35)
 * Eskimo armor increases damage of Ice weapons by 10%, reduces contact damage taken from cold enemies, grants immunity to Frostburn and Glacial State, and grants cold immunity in Death Mode.
 * Molten armor's set bonus increases true melee damage by 20%, provides the Lava Charm effect for 5 seconds, and the Obsidian Skull effect.
 * Meteor armor's set bonus has been nerfed to reduce the mana usage of the Space Gun by 50% (instead of 100%).
 * Beetle Shell's set bonus now makes the player take 10% less damage per beetle orb spawned (instead of 15%).
 * Spectre Hood has been buffed to decrease magic damage by 20% (instead of 40%).
 * Spectre Mask's homing projectiles have been nerfed to deal 30% less damage.
 * Solar Flare armor's defense is increased to a total of 94, and the dash distance performed by the Solar Blaze is increased.
 * Vortex armor's stealth mode only provides 40% ranged damage instead of 80%, and 15% ranged crit instead of 20%.
 * Nebula armor's Life and Damage Boosters have been nerfed. The effect of the Damage Boosters is halved to increase damage by 7.5%/15%/22.5%. The effect of the Life Boosters is halved.

Weapon Balance
The Calamity Mod re-balances a significant amount of vanilla weapons by buffing or nerfing certain attributes such as damage, granting auto-use, and changing mana costs.

Other

 * Gems and herbs obtainable through the Glimmering Gemfish and the Stuffed Fish, respectively.
 * Several vanilla crates include Calamity-based loot.
 * Corrected the Daybroken debuff's tooltip misspelling.
 * The Titan Glove, Power Glove, Mechanical Glove, or Fire Gauntlet now boosts true melee damage by 10%.
 * The Fire Gauntlet's melee speed and damage have been increased from 10% to 14%. Its recipe also has been changed, now requiring an additional 5 Scoria Bars to craft.
 * Several vanilla wings have been given stat boosts.
 * A list of those wing changes can be found here.
 * Hand Warmer increases life regen by 2 while wearing a full set of Eskimo armor.
 * All Town NPCs from both Calamity and Vanilla, as well as the Eternia Crystal are made immune to every debuff.
 * All Town NPCs take 2 times as much damage from all projectiles in Normal mode and 4 times as much in Expert mode. This is to make them more consistent with the damage the player takes.
 * Target Dummies will only be able to be hit when a boss is not alive; this is to prevent abuse of attacks that grant buffs or bonuses to the player.
 * Several vanilla items' tooltips have been changed.
 * Certain accessories, potions, and light pets' tooltips have been changed to reflect their effectiveness in the Abyss.
 * All vanilla wings now display statistics such as horizontal speed, acceleration multiplier, vertical speed and flight time.
 * All vanilla hooks now display various stats regarding tile reach, launch, and pull velocities.
 * The Magic Quiver's tooltip has been changed to say "arrow damage," rather than simply "damage."
 * The Warmth Potion provides immunity to the Chilled, Frozen, and Glacial State debuffs. The tooltips of the item and buff have also been changed accordingly to reflect this.
 * Additionally, damage dealt by Cryons, Angry Dogs, Ice Claspers, Aurora Spirits and Cryocores count as cold damage and therefore are resisted by the Warmth Potion.
 * All Flasks affect Rogue Weapons.
 * Bottled Honey now gives Honey Buff for 2 minutes on consumption
 * Flask of Party affects all projectiles.
 * The Invisibility Potion grants several boosts while holding certain Rogue Weapons:
 * Holding rogue bombs increases rogue weapon projectile velocity by 10%.
 * Holding rogue boomerang boosts rogue damage by 10%.
 * Holding a dagger increases rogue stealth regeneration by 20% even while moving.
 * Holding a javelin boosts armor penetration by 5.
 * Holding a spiky ball increases rogue critical strike chance by 10%.
 * All items with a max stack size of 99 and all types of bombs and dynamite are changed to have maximum stack sizes of 999.
 * Additionally, Pirate Maps and Snow Globes can stack up to 20 instead of 1.
 * Sandstorms cannot occur until the Desert Scourge is defeated.
 * Certain spawn-modifying items are buffed:
 * Water Candles now increase spawn rates by 48.15% and maximum spawn count by 65% from 33% and 50% respectively.
 * Battle Potions now increase spawn rates by 150% and maximum spawn count by 140% from 100% and 100% respectivey.
 * Peace Candles now decrease spawn rates by 30.07% and maximum spawn count by 37% from 23% and 30% respectively.
 * Calming Potions now decrease spawn rates by 35.90% and maximum spawn count by 44% from 17% and 20% respectively.
 * The Sandstorm's Mighty Wind debuff will be disabled if a boss is active.
 * The Heartreach buff now increases the grab range of all healing projectiles by 50%.
 * The Chaos State debuff now lasts 10 seconds, up from 6 seconds if a boss is alive or an event is currently ongoing, and now prevents the usage of teleporting items like the Rod of Discord instead of damaging players upon using them.