Materials (Mainly Ore)
Ore generated after the Perforators or the Hive Mind is killed
Aerialite Ore
Evil Tyrant and upcoming (whoops not anymore) Final Boss of Calamity
Yharim
Lord of Slime and controller of the Crimulan and Ebonian slime paladins.
The Slime God
First Rogue weapon crafted from Spider Webs
Web Ball
Crimson, Corruption, Hallow
Ore generated after Cryogen is killed
Cryonic Ore
Brilliant machinist who created the Mech Bosses, Wulfrum enemies, and the Exo Mechs.
Draedon
Forgotten clone of the Brimstone Witch
Calamitas Clone/Calamitas Shadow
Final Melee Class Weapon, crafted from Miracle Matter
Exoblade
One Ocean always generates as this biome
Sulphurous Sea
Galactica Singularity
Yharim's pet dragon and person guardian since birth, has a message to his master
Jungle Dragon Yharon
Exalted goddess made for one purpose, to erase all sin from Terraria. Enrages at night.
Providence the Profaned Goddess
Weapon Line that spans throughout the entirety of Calamity. Begins with the Biome Blade and Forgotten Ark.
Ark of the Cosmos
Biome where the Brimstone Elemental is fought
Brimstone Crag
Final Ore of Calamity. Used only for the strongest of crafting. Not a boss drop.
Auric Ore
The Brimstone Witch, brought to evil after her family and home was destroyed by Yharim. Bonus points if you can name her brothers.
Supreme Calamitas. Catastrophe and Cataclysm.
Draedon's finest machines. Commonly considered the "Final Boss" alongside the Brimstone Witch.
Exo Mechs
Gun dropped from the Devourer of Gods used in a certain very lethal glitch.
Norfleet
The Biome beneath the Underground Desert
The Sunken Sea
A special material, crafted from many different materials, but mainly a certain drop from Draedon's finest machines. Made for the strongest weapons of each class, (e.g. the Exoblade.)
Miracle Matter
Primordial God of Light and demiurge to the world of Terraria. Heavily related to the Terminus and the Rock.
Not expected for anyone to get this correct.
Xeroc
Monstrous sea beast and siren fighting together. Summoned by killing the siren's illusion in the sea.
Leviathan and Anahita
Last Gun in the Onyx Blaster upgrade line
Onyxia
The biome that appears from a fallen star once hardmode begins. NOT the Hallow. Full name required.
The Astral Infection.