The Jagged Crown is a symbol of office for the High King of Skyrim, a symbol of the might and power of the ruler of the Nords going back to the time of High King Harald (1E 143-221), or even before. Legend holds that it was forged from the bones and teeth of ancient dragons by Harald himself. A portion of the power of every king who has worn it is said to be contained within.
Jagged Lens of Compulsion
The Jagged Lens of Compulsion was an ancient Chimeri relic from the migration from Summerset. In the hands of the wrong mage, the lens can be used to entrance mortals, making them slaves to the user's will. Despite its dangerous nature, the academy of Shad Astula decided to keep the relic in its original location in the temple, still linked to the Shad Astula Underhalls.
During the Interregnum, the Jagged Lens of Compulsion was used by General Darvasen to enslave the students of Shad Astula and bolster the dwindling ranks of the Maulborn. Darvasen, the former assistant to Arch-Mage Valeyn, was previously expelled from the school for experimenting on another student using the Jagged Lens. A disgruntled Darvasen passed his knowledge of the Lens on to the Maulborn, and assisted them in their invasion of the Academy.
Shortly before the invasion occurred, the Vestige snuck into Shad Astula by dishonestly acquiring an invitation to the exclusive Academy, and stopped Darvasen with the help of three other students. The Jagged Lens was destroyed to free the students who had been enslaved during the Maulborn incursion.
Jewel of Fire
Legend has it that the Jewel of Fire is a star fallen from the sky, for it glows with an inner flame. The Jewel was used by Jagar Tharn to store the power of the Staff of Chaos, so that if anyone tried to recreate the staff it would be useless. The Jewel played a large role in the Imperial Simulacrum.
In 3E 389, Jagar Tharn stole the Staff of Chaos from Barenziah's court, and used it to imprison Emperor Uriel Septim VII in the realm of Oblivion, also killing his apprentice Ria Silmane so the Elder Council would not learn of his betrayal. Tharn wanted to make sure no one could release the emperor, so he attempted to destroy the staff. However, since the Staff of Chaos is indestructible, it was instead split into eight pieces, which Tharn then hid in forgotten, dangerous places throughout Tamriel. Tharn then made sure that no one could ever recreate the staff by draining its magical power into the Jewel of Fire, which he kept hidden in the Imperial Palace.
Jode's Core is a powerful, lunar artifact that has been coveted by even the likes of dragons for thousands of years. It has an appearance of a large, glowing blue sphere with power overflowing that makes it comparable to the appearance of a star. It is located in the Plane of Jode, a realm associated with Jode.