Fromsoft games are known for their deep and winding lore. Getting to the bottom of anything requires dives into the deepest parts of the world. Finding the obscure information therein will piece together and explain the larger picture. That's what will be explored now within the world of Elden Ring.
The Tarnished take the stage in the 2022 title - Elden Ring. They are a different breed than the Undead seen in the Dark Souls series, the knight of Demon Souls, or even the Hunter in Bloodborne. Though many will liken them to their predecessors, the Tarnished have their own origins and lore tied to their lineage.
*This post contains some spoilers. Read at your own discretion.*
The Homeland
Before understanding who the Tarnished are, one must understand their home and history. Tarnished were once inhabitants of The Lands Between prior to gaining their current title. It was a kingdom ruled by the Greater Will through its Elden Ring vessel Queen Marika the Eternal, who watched over the Erdtree.
Queen Marika was the vessel of the Elden Ring and ruled over the land with her male half - Radagon. Being the vessel of the Elden Ring gave her the status of Goddess, and she was to rule over the Lands Between, but there were those that would not hear of such a thing. She and her consort-husband, the Elden Lord Godfrey, would fight all of those in opposition to the Erdtree.
Eventually, she removed the Rune of Death from the Elden Ring as she desired a world without Destined Death. This later prevented the Tarnished (who fell from the Grace of the Erdtree) from dying, leading to their banishment from the Lands between. It wasn't Queen Marika's only defiance in the face of the Outer God that helped her ascend to Godhood. She and Radagon were locked away for her crimes.
The Lost of Grace
The Queen's first husband, the queen-consort Godfrey, was the first Elden Lord to exist. As the Queen's husband, he sought to do his Goddess' bidding, thus earning him the title of Elden Lord. He would go on to help her conquer the Lands Between for the Greater Will. Eventually, Elden Lord Godfrey would also become the first Tarnished.
After facing his greatest foe, he lost the surrounding light showcasing Erdtree's favoritism. Something in the battle with the Fire Giant changed Godfrey. He no longer had his will to fight, and that was when he lost the Grace bequeathed to him as it was to all others in the Lands Between. Queen Marika the Eternal had no choice but to follow the Great Will and banish her husband and lover.
Others began losing the grace of the Erdtree and became Tarnished themselves. Each was banished from the Lands Between but unable to die due to Queen Marika's tampering with the Elden Ring. Eventually, Queen Marika's firstborn was killed, leading to the Shattering of the Elden Ring.
The Erdtree's Call
After the Shattering of the Elden Ring into Runes, the Demigods began vying for the right to become Elden Lord. As they laid claim to individual runes from the broken Elden Ring, the fighting waged on. Eventually, new areas were settled as no one superpower could claim all the runes to remake the Elden Ring. Time seemed to stand still as the battles raged with no true end.
The Greater Will's power was weakened by the Shattering and imprisonment of The Eternal Queen. The Erdtree began losing strength, and the grace of the land from the Great Will was becoming weaker. Turning its sights on restoration, The Great Will sought power beyond the borders of the Lands Between.
The Tarnished were called forth from their banishment. Now, they were given a chance to become Elden Lord if they could restore the Lost Grace by remaking the Elden Ring from the scattered Runes. Once back in the Land Between, few Tarnished could perceive the Grace. Those that proved their worth were brought to the Roundtable Hold, but some were called upon by another being. Two-finger Maidens would pick a select few Tarnished to give guidance to in hopes that the Tarnished would become Elden Lord.
Not all those Tarnished that returned to the Lands Between could keep the hope alive. They would succumb to becoming Bloody Fingers. These fallen Tarnished were corrupted by cessblood, and now they hunt their fellow Tarnished for fun. Delighting in the blood, they spill. They can no longer be brought back to the side of Grace, and Tarnished must end them or be ended by them.
Now, the Tarnished are left to fend for themselves in a world that abandoned them. All in hopes that one will become the Elden Lord and restore order to the Lands Between.