History VideoGame / TerrariaCalamity

** The Leviathan can be technically fought any time in the game since the ??? can spawn at any time.

* BattleInTheRain: When the Siren spawns, the rain starts falling. It's not always immediately noticeable, though[[note]]While effects of rain like Angry Nimbus spawning and Waterleaf blooming will activate instantly, the visual effects of rain can take up to a few minutes to start after the world enters a rain state[[/note]].

** Blood Moons can drop blood orbs that can be mixed with water for a nearly-limitless supply of vanilla potions, eliminating the need for mods. Wearing Bloodflare armor expedites this by heavily increasing the chance for Blood Moons and enemies to drop blood orbs, which greatly increases the overall yield over a period of time.

* BonusBoss: A number of the bosses aren't necessary for progression and are only fought to obtain better gear. The mod also adds (and is planning to add) Superbosses, endgame encounters that will challenge even a fully-powered player.

Once upon a time, in the land of VideoGame/{{Terraria}}, a mighty warrior named Yharim rose in rebellion against the Gods of the land, sparking a war that consumed the entire world for decades. His crusade scorched the earth, Gods and mortals alike perishing in his rage, until even he lost sight of the very things he fought for. Now, long after Yharim's seeming disappearance, a lone Terrarian awakens to face its remnants…

Once upon a time, in the land of VideoGame/{{Terraria}}, a mighty warrior named Yharim rose in rebellion against the Gods of the land, sparking a war that consumed the entire world for decades. His crusade scorched the earth, Gods and mortals alike perishing in his rage, until even he lost sight of the very things he fought for. Now, long after Yharim's seeming disappearance from the ruined, cruel world, a lone Terrarian awakens to face its remnants…

** Movement speed, building speed, and mana regeneration are significantly increased across the board, making exploration and construction considerably easier in the early game.

** Each ore has a slime named after it which drops said ore, in order to avoid exhausting the player from searching for new stretches of ore. It also helps players whose worlds either don't have Calamity ores or lost them at some point.

** The Goblin Tinkerer's reforging was changed from a LuckBasedMission to an upgrading system, where you will get progressively better reforges until always obtaining the optimal one after a certain number of reforges.
*** One of the new town NPC's will even return a percentage of your previous reforging expenses to you at no cost, which she apparently steals from the Tinkerer on a regular basis.

** Uelibloom ore is made from fossilized tree bark, resurfaced from the defeat of the Profaned Goddess.

** Cosmolite Bars are a mysterious metal from another dimension, dropping from the Devourer of Gods.

* FantasyMetals: Just like the base game, calamity has many of these
** Aerialite is a metal found inactive in floating islands, and is reactivated, allowing mining, once the hive mind/perforators are defeated. It can be used for various sky-based items.
** Cryonic bars are icy bars that are found underground after Cryogen is defeated. Previous versions of the mod also introduced frigid bars that dropped from Cryogen, and enchanted metal, which was sold by the Archmage.
** Perennial bars are floral and organic bars not unlike chlorophyte. It makes jungle-themed armor and generates upon defeating Plantera.
** Scoria is a volcanic metal which can be found in the depths of the abyss, and requires a strong pickaxe to mine.
** Cryonic, Perennial, and Scoria bars can be crafted together into life alloys.
** [[ThunderboltIron Astral]] bars come from the heavens, and can only be mined once the Astrum Deus is defeated.
** Uelibloom bars are made from fossilized tree bark, resurfaced from the defeat of the Profaned Goddess.
** Cosmolite bars are of the cosmos, dropping from the Devourer of Gods.
** Auric bars are crafted from rock imbued with draconic power, generating after Yharon is defeated.

* ObviousRulePatch: In vanilla ''Terraria'', the Zenith is intended to be a PurposefullyOverpowered InfinityPlusOneSword, and to ensure [[BraggingRightsReward you can only use it after clearing all challenges]], two of its ingredients drop only from FinalBoss Moon Lord. ''Calamity'', having extended the course of progression so that Moon Lord is no longer the final boss, changes the recipe to also require Auric Bars, thereby locking off the Zenith until defeating Yharon, at which point its power level is more on-curve.

** The Void of Calamity dropped by Calamitas provides a 15% damage boost while raining brimstone fire whenever invincibility is active, but gives -10% to damage reduction.
** The Dimensional Soul Artifact provides a 15% to all damage and crit chance, that can bypass the mod's caps for those stats. However, it also increases all damage taken by 25% as well.

** Auric bars are crafted from rock imbued with draconic power, generating after Yharon is defeated