Forged during the era when Grogar ruled over Equestria, The Polymorphic Vanquisher was meant to defeat him with its high repertory of elemental magic and its capability to change to many forms while also granting its wielder elemental powers. Grogar couldn't wait any second after learning the existence of such weapon and desired it for his own wicked plans, Gusty the Great and her comrades were forced to send the weapon away to another world since letting Grogar own this weapon was something they couldn't risk. Due to the abrupt change of plans, Gusty, and the Unicorn Warriors chose to steal away Grogar's power source instead of directly defeating him, since now they lacked the power to do so. After Grogar's defeat, the existence of the Polymorphic Vanquisher was lost from all records, the only ones that knew how to forge such a weapon kept the secret to themselves, disappearing as time went on.

Unbeknownst to most of the people. The Polymorphic Vanquisher was sent to the current world of Canterlot High, where it remained hidden for centuries, until an antique collector found it buried under the sand. Unfortunately, the collector found a fatal end after returning to Canterlot City, where a duo of mercenaries was sent to kill him and retrieve the weapon.

But there's one small failsafe for this weapon to prevent its power to fall in anyone's hands. Before sending it to another world, Gusty cast a spell under this weapon: "Only those with unyielding determination will be able to wield thy power." With this, the spell granted the weapon of enough consciousness to chose its wielder, and this spell makes it so that everyone can use the weapon, but not everyone can wield its power.

Currently, the leader of The Storm Guard wields this weapon and has unlocked a few of its forms.

Thunderblade: A blade that can be wielded with one or both hands, but it grants its wielder the capability to create slashes with electric nature. While also making the user able to move as fast as lightning and land electric hits with his/her punches or kicks.

Gale Guan Dao: Allows the user to wield the power of the wind and create whirlwinds by spinning it in circular motion, if spins clockwise, the whirlwind pushes, and the contrary happens when spins counterclockwise. The Guan Dao can be separated in two, making the user much lighter and capable of unleashing wind blades when charges a swing of one Guand Dao. The piece of cloth indicates the sense of the wind currents, North and South, but only the wielder knows which one is which.

Mount Melter: A blazing axe capable of slashing thorough many objects with its overwhelming heat that melts every surface, the lower part of the axe charges up both edges when it hits the ground with a certain amount of strength. Once charged, the axe is now capable of throwing a powerful fireball with a heavy but powerful swing. The axe grants the user the power to use flaming fists, which can burn their opponents with every hit.

Blizzard Bow: A bow that holds the power of the coldest ice, making the user able to shoot frozen arrows that can cripple the target. While also granting the power to create icy surfaces under the user's feet, enhancing his/her movement, by sliding and changing position quickly.

"That weapon... Since she got hold of it, she became extremely powerful, and drove her ambition to places I couldn't follow anymore. That helped me realize that I didn't want that life for me.... but... she didn't listen... and that's why we parted ways."