The new mods and addons expand on the progression with several new endgame bosses but also hardmode bosses
Summoned using a Pyro Key crafted from sand, some souls and Essence of Flame, dropped by desert enemies after Hardmode
His drop table is similar to the one from Cryogen, with every item modified to be in the theme of fire. He also drops the Desert Key to open the Desert Chest in the Dungeon post Plantera
A 100% troll boss, but still fun to mention: fought just after the Calamitas Clone, summoned by using a Clamitous Shell in the Brimstone Crag
Summoned by using a Sandstorm Core (post Lunatic Cultist item) on the portal of the Lost Colosseum, located somewhere in the underground Desert
Using it will open a portal to another dimension where you will find this boss
