Rites of Prime Banishment

The Rites of Prime Banishment is the ritual used to exile a god from the Material Plane and seal them behind the Divine Gate. The ritual involves the Prime Trammels to weaken the god and the Tome of Isolation to invoke the banishment.

The Prime Trammels
The Prime Trammels are long, javelin-sized spikes of platinum can be attached to a wounded god to aid in the Rites; the more wounded the god, the easier they are to attach. Although to craft a single Trammel requires "the strength of a titan" and "the ingenuity of a madman", the tools to craft them are ordinary. The design is unknowable for the most mortals.

Each Preme Trammel requires both blacksmithing and tinkering skills kept secret by Ioun, involving a large amount of pure platinum (1500 platinum per trammel), smelted down into workable bars, and infused with a fragment ("bead") of divinity, shattered across the anvil. The fragments can be granted by Deities of Exandria, requiring a great sacrifice of their power and can be done only once, being lost "until the seal is broken". Each bead is a small, smooth oval and in its appearance represents the god/goddess it was a part of: Ioun's has a faint whitish-gray glow, the Dawnfather's bead has a faintly yellowish-glowing, and the Raven Queen's bead is jet black in color.. To properly shatter a bead, the blacksmith must pass DC 25 Strength Check and has at least three attempts.

In the next step, the metal bars must be stretched to a tip, taking shape of a javelin-like rod, and use the vise to twist the heated metal, as a prerequisite of improved conductivity of the divine energy across the Trammel. In a final stage, using the chiseling tools, the runes are engraved on Trammels that match the incantation from the Tome of Isolation. As with fragments, the Trammels' appearance represent each deity that bequeathed an element of their power: one Trammel glows yellow, another sky blue, and the third emanates a black shadow from its runes.

Properties
The Prime Trammels can be thrown or thrust into a foe (an improvised weapon attack using Strength or Dexterity, attacker's choice) at a range of 20/40. Upon a hit, if the target has taken enough damage to leave an open wound, the trammel may embed itself within the weakened opening.

The Tome of Isolation
The Tome of Isolation is thin, grey leather-bound tome appears damaged and ancient. It has no title on the spine and is filled with blank pages. When activated, the text emboldens, describing the method to invoke the Rites, in what appears to the reader as Common language.

Properties
As an action, the one who holds the Tome of Isolation can expend a spell slot of any level higher than 3 into the book. The cover and the internal pages glow with the hidden text of the Rites of Prime Banishment. This text remains for 1 hour.

While legible, they can spend an action to invoke the Rites of Banishment against a target. The target must make a wisdom saving throw (DC 10, +5 for each Prime Trammel fused to the target). On a failure, the target is banished and sealed, and this book is immediately teleported to the Endless Athenaeum. On a success, the text becomes blurred until the end of your next turn."

History
The ritual has only been used twice in the history of Exandria.

First, during the events of the Calamity, the Prime Deities sought to re-imprison The Chained Oblivion. It took the full might of Pelor, with the blessing of Avandra and a near-fatal blow to Ioun, to defeat the mad god and complete the ritual. The banishment involved the Prime Trammels forged by one of the Prime Deities, The Allhammer.

Long afterward, as Vecna sought ways to strengthen his newfound godhood and expand his domain in Exandria, Vox Machina sought help of Ioun who knows of a long-unused, ancient method of banishing him behind the Divine Gate. But before she granted them with this knowledge, Ioun has chosen Scanlan Shorthalt as her champion, also giving him her blessing, and set to complete a timed challenged that prove them as worthy candidates. Once they fulfilled the objective of finding and delivering the Tome of Isolation, she descibed the ritual and lend them, granted them the Tome, and magically lended Grog and Percy the complete picture of the craftsmanship to make the Prime Trammels. They remembered it "only for as long as it's required".

In, Vox Machina]] traveled to The Allhammer's abandoned workshop to craft three Trammels of their own. They used one bead of divinity from Pelor, one from Ioun, and one from the Raven Queen. Grog, using his Titanstone Knuckles, provided the strength to work the hammer. Percy, aided by knowledge from Ioun, provided the ingenuity to design the Trammels and engrave their surface with runes. Vox Machina succeeded in fusing three of the beads of divinity into three Prime Trammels, though one may be more fragile than the other two due to difficulties during its construction. They spent 4500 platinum coins on three Trammels (1500 per Trammel).

Vox Machina confronted Vecna in his Ascended form atop the tower of Entropis. Keyleth, in the form of a planetar, completed the ritual to seal Vecna away beyond the Divine Gate.