Let's start this story with a few disclaimers - I do not own Terraria, or anything referenced within. The only thing I own is my original character, Artorias, and the actual story that you'll be reading. With that out of the way, I hope you enjoy this!
Prologue
Within the many lands of Terraria, a single man had founded a grand castle in hostile lands, like many before. His name was Artorias, a knight that had been rejected for his unusual ailment: a piece of heart statue had been stuck inside his torso, between the two lungs. While it regenerated his health at an inhuman rate, his breath was forever stunted.
Artorias had been quite the adventurer, regardless: he'd seen the marbled underground gardens, gone against sandstorms of incredible ferocity, even gazed into Hell itself. The man took pride in his abilities, and kept his people safe. This pride, however, was his downfall.
Nobody could ever be ready for the Crimson to take them.
Adorned with a suit of faded cobalt, its magical power lost to the ages, he set out. A fireball sentry was strapped to his back, awaiting activation, and a bladed 'yoyo' as large as his head stayed close at hand. He'd said his goodbyes - he now answered to the call of adventure.
~{θ}~
The first thing to reach him was the scent - iron and death permeated the air. With it came a drive to slay anything within - all knew the stories of corrupted land consuming entire continents. The land ahead was dominated by an almost tumor-like opening, and Artorias knew where his path lay.
With each horror he was forced to slay, Artorias grew more enraged. The Crimsoned land was seeping into his mind, further brutalizing his strikes with every foe felled. His rage was for naught, though, as a war cry full of wrath punctured his lung on the very statue that kept him going for so long.
The ground consumed him as he fell. Not a soul would see or hear of him for months.
~{θ}~
Eventually, the bloodied biome took over. It was a small island, regardless of any adventures to be had, and nothing could withstand the tainted land forever.
The inconcievable happened soon after - souls had been released from somewhere within the vast universe of Terraria. Long deceased rose with true vengeance, spirits claimed each other in wrath. Even the Bosses of Old feared what would become of this. Among the dread knights and wraiths, the Crimson itself spawned its own champion to hold its place.
He was clad in fleshy armor, made violet from its previously indominable color stewing within blood. A warped staff was at his back, shifting itself into an ichor-spewing sentry at command. A shield, adorned with the Mark of Cthulhu, welded itself to a large buzzsaw of bone as large as the champion's head.
And so came the rise of Sir Artorias, self-proclaimed Harbinger of the End.