Odin's Vault, publicly known as the Treasure Room and sometimes dubbed the Weapon's Vault, is a room in the Royal Palace of Asgard that holds various items and artifacts gathered by Odin in his course of victories.
The Vault was built deep within Asgard's Royal Palace. It was constructed to safely store any dangerous object that the King of Asgard came across throughout their time protecting the Nine Realms. As Odin is the current King of Asgard, it is usually regarded as "Odin's Vault." To keep a formal image, the Vault is spoken publicly as "Odin's Treasure Room."
During his peace-keeping reign, Odin has gathered several items, weapons, artifacts, and objects that displayed such catastrophic potential as to threaten Asgard, the Nine Realms, and the entire universe as a whole. Simply put, the Vault locks away "anything that has the capacity to cause Ragnarok."
The Vault is placed far below the Asgardian Royal Palace within the deep recesses of its most structurally sound fortifications. The path to the Vault is a long descending flight of stairs constantly guarded by some of Asgard's most elite.
The Vault itself is physically open for anyone to walk into and view what is kept within, following a straight path with chambers spaced out on both sides; however, each artifact on display is in fact protected with powerful enchantments to prevent anyone from simply taking what they see. Only members of Asgardian royalty, or high members of the guard, have the knowledge of dispelling the enchantments for access to the displayed artifacts. There are multiple levels to the Vault.
At the very end of the path on any level is another chamber, though this one is sealed with a complex physical barrier. This chamber is enchanted, though instead of a protection spell, it is a translocation spell to allow it to be opened from any floor of the Vault from its singular position. Housed within is the Destroyer automaton, which Odin has set to act as a sentinel within the Vault, prepared to eliminate any intruder that happens to actually make it all the way within the Vault.
Originally contained in the Vault due to its sheer destructive power, the Destroyer automaton is a suit of armor forged from Uru that is enchanted to operate on its own when not being worn, possessing mighty strength, immunity to conventional forms of attack, and the harnessing of a very powerful energy source that can be directed into grand beams of force. In an interesting twist, Odin has charged the Destroyer to also act as a guardian within the Vault, protecting the other items inside from possible intrusion.
A mighty warhammer forged of Uru, Mjolnir is a great weapon bearing several enchantments that make it one of the most powerful objects in Asgard. It was once used by Odin himself, originally in combat against his enemies but then later helped in reconstructing the Nine Realms. Strong enough to send targets flying, able to be hurled with great force across a vast distance and return to its thrower in mere moments, and channel the energies of its wielder through it to create powerful blasts, Mjolnir is regarded as much a "tool to build" as a "weapon to destroy."
The Infinity Gauntlet is an artifact that, hypothetically, is designed to be used in conjunction with the six Infinity Stones to make its wielder all-powerful. Supposedly, the Gauntlet is actually just a creation of one way the Stones could be used should they be joined together; the stones placed on the Gauntlet itself are actually fake replicas of the Infinity Stones, with the Gauntlet appearing to be nothing more than an elaborately designed, but otherwise simple metal glove.
The Tuning Fork is an object with one purpose alone, though the purpose it fulfills is potentially devastating. When activated, it summons the Lurking Unknown, an extra-dimensional being that gains power from the fear of others. This creature was responsible for the destruction of several worlds before bound to the Tuning Fork, where it is now used to test Asgardians warriors in a rite of passage.
The Eternal Flame is a mystical, inextinguishable fire that originates from Muspelheim. The source of power and life for the Realm of Fire, the Eternal Flame is tied to the ruler of Muspelheim, Surtur, empowering him with unlimited vitality and strength. So long as the Eternal Flame remains burning, Surtur can only be defeated, not destroyed; and when joined with him, amplifies Surtur's power to great levels and enhances all inhabitants of Muspelheim. It was placed within the Vault after Odin's battle with Surtur, which resulted in the Fire Giant's defeat despite his great empowerment.
The Warlock's Eye is an artifact with a powerful enchantment that bends the minds of others, enabling whoever holds it the power to control others. The enchantment is very difficult to resist for even Asgardians, with few being able to withstand it using their own willpower. It was brought to Asgard during Harokin's invasion, who ultimately failed at conquering Asgard despite the Warlock Eye's power. After Harokin's defeat, Odin placed the Eye in his Vault.
The Tablet of Life and Time is an artifact with an inscription of a powerful formula. The formula can be used to create a serum described on the Tablet as the "Lifeline Formula," which according to the Tablet can rejuvenate and heal its user, as well as granting them full evolutionary potential, bringing them to near immortal omnipotence. Translated correctly, the runes state, "Those who sit above in Shadow," a reference to possible deities that draw their life energies from Ragnarok.
The Tesseract was once contained in Odin's Vault. The Tesseract is a Cosmic Cube, a device built to harness vast cosmic energy for various purposes, though is generally used for a power source or great destruction. The Tesseract can take energy from space and use it to power machines, project energy, and translocate objects from one location to another. Unbeknownst to many, the Tesseract is actually simply a container for the Space Stone, one of the six Infinity Stones that has the power to manipulate the fabric of space itself. However, the Tesseract is no longer kept in Odin's Vault, having been secretly left on Earth after the Frost Giant Invasion of Midgard by Odin himself for unknown reasons.