Had a cool idea, decided to run with it. This is a general's blade, particularly appropriate for a Sidereal campaign.
When Kai Nu was called to the House of Battles, it was given to him to see how he would die -- in battle against Creation's enemies. This fate, he did not accept, and sought to shape a blade which would cut away the strands of fate that bound him to his death.
Each night, he dreamed of the sword he make. He dreamed its shaping, its forging and its quenching. But when it was done, each night, he looked up to see the Maiden of Battles before him, shaking her head in sorrow. The blade, he knew, was unworthy, and he awoke each morning to the sound of it shattering.
Kai Nu became obsessed with creating the blade. He delved deep into the arts of the forge, deeper than all but the greatest of the Five-Score Fellowship, as deep as some of the ancient Lawgivers. He bound Aulveia to his will and studied a year and a day at the feet of the Forge of Night. He sought the mad insights of the raksha and the secret lore of the Underworld and all these things, he applied to the forge in his dreams.
At last, the day of his fated death approached. On that night, he dreamed more vividly than ever before. He shaped the blade with all his art and skill, forged it in the fires of his determination. And when it came time to quench the blade, he felt the Maiden of Battles take it from his hand. She smiled at last, as she pierced him through with it, and as his heart's blood finished the quenching he died without regret.
In the morning, Kai Nu was no more, and in his place was the blade his dream had forged.
Inevitable Necessity (Artifact ****)
Inevitable Necessity is a starmetal grand daiklave of surpassing craftsmanship; it is unornamented, but no ornament is needed. Anyone who gazes too long into the blade's mirrored surface will begin to see reflected there the great battles of their lifetime; unfortunately, these images are possible futures only, and too blurred to make out useful details.
The power of Inevitable Necessity comes from its tie to the Loom of Fate, forged by the aborted destiny of Kai Nu and the power of the Maiden of Battles. The attuned wielder is always considered to be under an ascendent destiny of the Gauntlet, which does not count against his maximum number of astrological effects. So long as he fights only necessary battles -- either to himself or to Creation -- he may choose one of the four ascendent effects to apply until the battle's end. He may make this choice anew with each battle.
If the wielder is reckless, he may draw more deeply on the blade's powers over Fate. Inevitable Necessity has an effective Endurance pool (as though it were an astrological effect) equal to the wielder's Essence, which may be applied to any Resplendent effect of the five colleges of the House of Battles. This pool recharges at one point per day, but the wielder is advised to be cautious; the Paradox cost of each effect is increased by one die, to a minimum of one die. This adds normally to Paradox gained from other effects, if the wielder is a Sidereal Exalt.
Should the wielder acquire ten points of Paradox while wielding Inevitable Necessity, the blade's fate subsumes their own. Instead of inflicting Pattern Bite, the pattern spiders and the Loom arrange for the wielder to encounter a dangerous battle against Creation's enemies. The wielder suffers the Flawed Fate of the Chosen of Mars until he survives this battle or dies in it, driving him to seek ever-greater conflict and fulfill Kai Nu's abrogated destiny. Once the battle ends in victory or defeat, the wielder's Paradox score is discharged.
The free access to a Sidereal-only schtick would normally make this weapon Artifact 5, but its tendency to eventually force its wielder into battles he doesn't (initially) want is a major drawback. It's roughly comparable to the Crimson Bow of Ai -- less powerful but much more flexible -- and thus is Artifact 4.