I couldn't miss the chance to practice my drawing!
The interdimensional key is an artifact and important story element in Final Fantasy XIV: Dawntrail. It is a crystal capable of opening portals between the Source and its reflections. The key's origins are unknown, but it seems to have a connection to Azem, whose symbol appears on it when it is activated. While contained inside an electrope case resembling a trophy or hourglass, that was a modification done by Preservation; the key itself is only the crystal.
History[]
Before Final Fantasy XIV[]
The artifact, which came to be known as the interdimensional key, was a crystalline object originally revered by the inhabitants of South Sea Isles in the Source. Its true origins are unknown.
During the Fifth Umbral Calamity, which began the Age of Endless Frost, the Lalafell inhabitants of Aloalo Island attempted to save themselves by praying to the artifact, inadvertently opening a portal through the rift into the Ninth reflection of the Source. The surviving inhabitants traveled through this portal finding themselves in a new world, where they integrated to the world and its peoples.
Many years later, the Ninth turned heavily towards lightning in its aetherial aspect, with thunderstorms becoming commonplace. Within the Kingdom of Alexandria, a black ore dubbed as electrope was discovered, capable of absorbing lightning aether. When the former Aloalo refugees, now known as the Milalla, imbued electrope with arcanima circuits, its potential was increased substantially, as with certain arcane patterns, electrope was capable of transforming lightning aether into other elements.
The scarcity of electrope eventually led to a war over resources known as the Storm Surge, which ended in near total annihilation of the world as a Flood of lighting began to raze the star. Alexandria survived through the efforts of the young scientist Calyx and his scientific collective, Preservation. They covered Alexandria inside a dome projected from a massive tower of electrope, called the Everkeep, which they constructed atop the ruined Alexandria castle. They learned to utilize electrope to extract souls and separate memories from them. Souls could then be used as soul cells for the living, allowing them to come back to life should they die from an accident, while the memories were used to create the Endless, simulacrums of the deceased that lived a life of ease and their happiest moments within Living Memory, the highest floor of the Everkeep, forever. This method was also used to create Endless Sphene, an Endless version of Sphene Alexandros XIV, the last queen of Alexandria, who would rule Alexandria forever under Preservation's control.
As the Endless required a constant supply of aether to be maintained, Preservation began to study the key that had come into their possession to learn how to open portals to the Source and other reflections to obtain the aether necessary to maintain their goals. Preservation hired two Milalla scientists, Robor and Alayla, to research the key. The result of this research eventually led into the creation of an electrope gate on Living Memory that connected the Ninth to the Source. The other side of the gate was constructed in the continent of Tural, within the Skydeep Cenote, located within the forests of Yak T'el. When Robor and Alayla discovered that Preservation intended to steal aether from the Source, they rebelled and defected, stealing the interdimensional key. To keep it from Preservation's hands, the pair opened the gate and spirited away it, as well as their infant daughter, to the Source, where they encountered the Dawnservant of the nation of Tuliyollal, Gulool Ja Ja, who had hired Sharlaan researcher, Galuf Baldesion, to help investigate the Skydeep Cenote and the gate. When Robor and Alayla opened the gate and crossed the rift, Alayla gave their baby to Galuf, and Robor handed the key to Ketenramm the Blue, before heading back to the Ninth, closing the gate. Nobody could make out what the key was and what it did, but Gulool Ja Ja took it for safekeeping.
Final Fantasy XIV: Dawntrail[]
Twenty years later, Gulool Ja Ja held a rite of succession for his children, Zoraal Ja, Koana, and Wuk Lamat, as well as the chosen of Mamook, Bakool Ja Ja, to succeed him as the next Dawnservant. Wuk Lamat won the rite with the help of the Warrior of Light, Krile Baldesion, and Alphinaud and Alisaie Leveilleur. Zoraal Ja, who was disqualified during the rite, conspired with his assistant, palace seer Sareel Ja, to steal the key and use it to open the gate in Skydeep Cenote. Zoraal Ja struck Sareel Ja down after reaching the gate, and opened it and traveled to the Ninth. He made a covenant with Endless Sphene and became the King of Resolve of Alexandria. Now that the key had been returned, Sphene and Zoraal Ja used it to induce interdimensional fusion, taking the Everkeep and its surrounding area, barring Living Memory, and fused it with the Yyasulani region in Xak Tural, bringing with them the dome of lightning aether that surrounded the kingdom. After crossing the Dome, Zoraal Ja invaded his homeland, killed Gulool Ja Ja, and challenged Wuk Lamat to invade his new kingdom. This conflict eventually ended in Zoraal Ja's death, with Endless Sphene seizing the key to use it to harvest aether from other reflections of the Source to keep maintaining the Endless in Living Memory.
The Warrior of Light, Krile, G'raha Tia, and Wuk Lamat followed Sphene to Living Memory to stop her. After shutting down the terminals maintaining the Endless, they proceeded to the central Meso Terminal and fought their way to Sphene, where she had integrated herself into chimeric machine known as Queen Eternal, linked to the key to enact her plan. As the Warrior of Light was forced to battle Queen Eternal alone after she ejected the others, they used Azem's crystal to summon reinforcements. When they did, Azem's symbol appeared on the key, indicating a connection between the crystal and the key. The Warrior defeated Queen Eternal when Wuk Lamat was able to join the battle and reach out to Sphene. Sphene was unable to maintain herself now that Meso Terminal had been shut down. She apologized for her deeds and entrusted the key to the Warrior of Light against her programming, trusting them to keep it safe.
Queen Eternal's defeat did not go unnoticed by Calyx who had become an Endless himself and now intended to create even more Endless, believing they were the next stage of evolution, as he loathed the idea of mortal vessels. He created a simulant Sphene to masquerade as the queen to coax Alexandrians into registering new type of neo-regulators to become Endless. He developed interest in the Warrior of the Light who carried the key, wanting it back to gain access to other remaining reflections and their aether.
Calyx would employ various methods to reclaim the key from the Warrior's possession, first attempting to assassinate them using a lightning strike, then luring the Warrior to the old Alexandria Castle where he would pit a machine duplicate of Zelenia Triantafylli against the Warrior. Both methods failed, leading Calyx to develop a new means to require the key and further his plans to create more Endless. His plan involved stealing the corporeal aether of those who did not wear regulators while reinciting the fear of death in Alexandria's citizens. Calyx offered to end his "harvest" if he was given the key, but the Warrior of Light refused, knowing that Calyx would merely find new victims within other shards. Likewise, any of the original Sphene's attempts to convince Calyx to cease his mad vision for mankind's evolution would fall on deaf ears.
Calyx initiated his plan to destroy the Warrior of Light and reclaim the interdimensional key, inviting them to where his memory was stored deep within the Meso Terminal, and using the citizens' fear of death to fuel the summoning of a primal, Necron, that would grow stronger with each defeat thanks to representing the fear of death. Though Necron proved dangerous and risked defeating the Warrior of Light and their party through sheer attrition, Sphene thwarted Necron's source of strength by speaking out to her people, getting them to remember the good in their lives, to honor a life long lived, feelings that proved stronger than their fears. With Necron's strength diminished and his memory core threatened, Calyx transferred his memories to another location, narrowly surviving, but his plans were ruined without the key.