Whispers of the Coldest Iron

Tragedies are the most beautiful of stories, of course, but... surely 'tis only that? A fable for the children?

— sheltered nobleman

Mortals have a sad existence to the wondrous beings known as fey. Their lives are painfully short, and they don't even come back when something kills them - it's really quite a disappointment. Naturally, the fey seek to play with them as much as possible. To find ways to help these tragic souls, so different to their own.
And equally naturally, the topic of fey is one that brings up mixed reactions in the common folk of all Istralar. Graceful creatures such as nymphs and dryads are the centrepiece of every bard's tales, but too often do young would-be adventures run afoul of capricious nereids and their drowning kisses instead. Farmers welcome the help of brownies but should a boggle make an appearance, out comes the headsman's axe.
When the more powerful of fey alight from the First World, mortals rightfully flee. A beautiful muse may be a baobhan sith in disguise... or the Wild Hunt could have arrived.

Ah, feyfolk. Is there any wonder we humans write tales to warn our children? Don't give your name! Don't walk into a circle! And when in doubt, wield cold steel against them!

— wise mother

Summary

The myths of the Coldest Iron begin with the telling of a love story. A beautiful mage fell for the prince of her home, but could never be with him: he was royalty, and she was nothing. She used her powers to sneak into his gardens at night to meet with him anyway, and the two fell deeply in love. It was not to last, for his father found out soon enough, and she was banished from the kingdom.
Alone and upset, the mage - commonly known as Niamh - took it upon herself to become his equal. She sunk deep into the depths of arcane knowledge and found that her answer laid with the fey. She entered the First World with all of the gold and magical crafts she could, and hid her name. The faeries teased her, but she played along - she played their games, knowing full well that her life was on the line with every dance, until they guided her to the most powerful being they could think of. To the merry soul known as the Lantern King.
Niamh made a deal with him after much cajoling and jolly humour. He would help her claim a small realm of her own and make her a princess so that she could marry her prince, and she would in turn give him something from her past, her present, and her future. She considered it and accepted, and so their deal was made.
From her past, he took her memories of her mortal life. She was a princess of the First World, of course, she always had been! From her present, he stole her guise: she was a fey princess, now, and one of the most beautiful alive. Though she recognised herself in the mirror, there was no humanity left to her! The Lantern King found her ire hilarious, and sent her on her way.
She sought out her prince with haste, and found him now older and ruling the kingdom she had wished to claim. There was no king in their way now, nor had he moved on from his love for her. He was stunned with her form and upset when she told him what he'd done, but he had been searching for her for so long that he gladly looked past the changes. They were wed, and lived happily for a year and a day.
It was then that the Lantern King's trick came to light. What he had taken from her future was her happiness. The people of her lands disliked her human husband, and the people of her husband's thought her a succubus witch. The days grew harsher as summer faded to autumn, and it was at the start of winter that Niamh sought out the Lantern King once more.
She did not find him this time. Nor did she return, and her husband grew desperate. First, he sent out his guard. Then it was the army, then the most powerful adventurers he could find. When all results came back empty-handed, his anger blazed into cold fury. He brought before him the most powerful craftsmen in all the lands and bid them forge him a blade that could cleave the First World in twain. It took exactly three years, three months, and three days, but they accomplished his task and brought to him a blade forged of the purest cold iron and touched by the deepest shadows of the Shadow Plane.
So the King set out into the First World. When the faeries greeted him, he cut them down in silence. Satyr songs were cut off in bloody shrieks. Dryads tried to flee their trees, but his horse, with its cold iron horseshoes, was faster. Eventually, a gnome - one of the denizens of the First World, not one of the Material Plane - was granted leave to live long enough to tell him of a beautiful queen of the fey, one of the Eldest, who might have been responsible. The Green Mother, a self-proclaimed guide for natural selection. Stunningly beautiful, but a devastating seductress that disavowed standard morality.
With the gnome left trembling behind him, the King rode forth to seek out this Green Mother. Fearing his blade, the fey led him to her hanging bower - and he charged in with no regard for her many petitioners, each scrambling back from the dark-armoured mortal. She was as beautiful as they claimed - long green hair tumbled down her gown of vines, and lips carved out of bark twisted in a smile for him as he charged forward. He demanded to know where Niamh was. She laughed at him.
In the next moment, she was screaming instead as with one swing, the King decapitated the Eldest. With another few hundred swings, he began to cleave the bark of her skin, burning tears pouring from devastated eyes. She was lost, he knew it! Niamh was dead, and he had failed!
It was during his fit of rage that the Green Mother's laugh sounded again: colder, and altogether more sultry than before. He looked up from her body to see her once again as vines swelled around him, preventing him from charging. For it had not been the Green Mother that the King had attacked. His eyes dropped to the still-warm corpse, and he screamed. Niamh was dead. He had failed - he had failed in the most cruel of ways.
The Eldest was not swift enough to prevent the King from lifting his sword and thrusting it through his own chest, but that didn't change her amusement. Niamh was fey, due to the actions of the Lantern King, and fey were immortal within the First World. His actions had accomplished nothing more than his own demise, and when Niamh awoke to find her dead lover atop her, the Green Mother mocked the young princess's failure.
So distressed was Niamh that her already broken mind shattered entirely, and she fled the Green Mother's domain with her husband's body and sword before any could stop her. Still empowered with arcane magic, she drew on as much power as she could and bound her soul to the blade. The fey were a menace, and she would see them ended! Her final act was to open a rift to the Material Plane and cast her love back to his home - sword still in hand.
He was a warning. His blade, a gift. With both, the message was clear:
Do not trust the fey.

It's a bit of a twisted myth to tell the children, to be honest... my son's been having nightmares for weeks.

— regretful father

Historical Basis

Cold iron is known to all adventurers as the most useful weapon against demons and fey - though it is not always easy to come by, and stubbornly resists enchantment. Though far less versed in mysterious steel mined in the depths of the earth, many commoners have still heard of cold iron and its properties. In children's fables, storytellers oft confuse it with common steel; wielding steel against the fey is no more effective than a weapon of iron, however.
The mystery blade hinted at in the Coldest Iron myths is likely to be an extrapolation of these anti-fey abilities combined with the arcane might a spellcaster can throw upon a blade; if the item actually exists, it is shrouded in secrecy. True artifacts and weapons do exist: the empyreal lord Vildeis wields a cold iron blade known as Cicatrix, Champion Ypolita outfitted many of her crusaders with enchanted longswords during the Shining Crusades, and the Maleficus Spike combines the properties of cold iron with those of adamantine to keep demons at bay.
But none of these items are quite so powerful as the alleged Blade of Coldest Steel, and so its existence is relegated to that of myth until proven otherwise.

Date of First Recording

5597