In the most ancient Age of Gods, the Underworld was not merely a concept or a nebulous space. It was a domain of death, buried deep underground, within countless abysses.
In other words, if you dug deep enough, you could reach the Underworld and meet its sole goddess.
Within a sunless canyon, rugged paths were covered in endless shadows. A pure black river flowed into the distance. Ereshkigal, diligently crafting cages to imprison souls, sighed helplessly, "Sigh… sending so many souls to me every day. Humans, other races... what are you all doing?"
"Can't you be a bit more peaceful? That King Gilgamesh..."
As various screaming, twisted soul fires burned, numerous spear-like cages stood on both sides.
Due to the Underworld's unique nature, souls arriving here after death were all spirits without physical bodies.
Over time, these souls would lose their memories and wisdom, gradually reverting to the most basic primordial substance before dissipating and transforming back into mana to replenish the world.
Unable to bear watching souls dissipate like this, unable to bear seeing them perish so utterly, the mistress of the Underworld, Ereshkigal, outwardly appeared as a cold and ruthless goddess, but in reality, she cared deeply for all living beings.
She worked hard to create protective devices called 'Kur Kigal' (Spear Cages), crucial tools for slowing the dissipation of souls.
"You noisy bunch, just get inside quietly and behave!"
Her words sounded tsundere and angry, but the goddess's heart was soft; she didn't want any soul to simply vanish.
Busily maintaining the Underworld's operations, she suddenly looked up.
"Who's there?"
Standing up warily, she looked into the abyss before her. The passageway, usually all too familiar, now set off all her internal alarms. Her intuition sensed an aura of fear.
Simultaneously, the residents within the countless Kur Kigal beside her also felt it. No longer lethargic, they sensed immense danger.
[Due to your existence, Tiamat altered her Saint Graph, discarding most of her instincts, aspects as the Daughter of Fate and Primordial Mother into the Sea of Imaginary Numbers. Tiamat, now formally existing as a goddess, was no longer rejected by the world of Mesopotamia.]
[Your fingertips touched the node representing the other world. Without the World's Will hindering you, Tiamat and you easily returned to Mesopotamia.]
[Looking at the dark, Underworld-scented abyss around you and the golden-haired, red-eyed goddess before you, her exquisite face full of panic and a ditsy expression, you found her somewhat familiar.]
[After a moment's thought, you remembered she was the Underworld Goddess Ereshkigal.]
"Mo-Mother Goddess Tiamat?"
To all the gods of Mesopotamia, Tiamat was the Mother Goddess who created everything. Memories of this goddess were faint, as by the time Ereshkigal was born, Tiamat had already been exiled by Anu and Marduk.
Despite this, Ereshkigal could recognize Tiamat's existence at a glance. Even though the Primordial Mother had altered her Saint Graph, Tiamat was still Tiamat.
The connection stemming from bloodline and spiritual origin would not let Ereshkigal mistake her.
Her crowned body trembled uncontrollably. At this moment, Ereshkigal felt only despair.
What to do when the Primordial Goddess suddenly descends? How can I stay safe? Urgent, please answer!
…
Outside the temple Meslamtaea, located among the mountains of the Underworld, squads of Galla, guards shrouded in dark mist, patrolled.
As the Underworld guards exclusively belonging to Ereshkigal, these loyal guardians had slender builds, carried weapons at their waists, lacked much intelligence but excelled in loyalty, and were numerous.
Due to the Underworld's unique nature, it was separated by seven gates. The souls in each region differed: for example, regions one to two held humans, three to five held other races, six held those strong in life, and the seventh was Ereshkigal's own residence.
Inside the temple of the seventh region, usually silent with only Ereshkigal's presence, now housed two additional people.
"Tia, good morning."
"Morning, Ryu."
Logically speaking, compared to the sunless Underworld, the world inside Rashomon had a better environment.
After all, Rashomon was a self-contained world, and even if small, it was still a world, acknowledged even by the World Bubbles in the Sea of Imaginary Numbers.
It contained the most basic lifeforms like plants and water, with flowers visible everywhere. However, in Tiamat's view, the land she resided on was utterly unimportant.
"Ryu."
Abandoned by the gods, forsaken by the world, born as the Primordial Mother, Tiamat was like a used tool. The first thing a blind person who regained sight would do is discard their white cane. Tiamat was like that white cane, lacking presence.
She had wandered lonely and desolate for an unknown length of time until she met Ryuya. She then realized she didn't need to love everyone, nor did she need to love her children unconditionally.
She, too, was someone who received love from another, who obtained her true, one and only existence.
She anchored the entire meaning of her existence onto Ryuya. For Tiamat, any world with Ryuya was perfect, and a world without him was useless.
Looking at her beloved waking up beside her, Tiamat didn't mention she had woken up long ago, having been mesmerized just watching Ryuya's sleeping face.
"Tia, is Ereshkigal awake?"
After arriving in the Underworld and meeting Ereshkigal, contrary to Ryuya's expectations, Ereshkigal's reaction to Tiamat's appearance, after the initial shock, was delight. She seemed to have no sense of crisis.
Ryuya guessed that the truth about Tiamat's exile had likely been concealed by the ancient gods, who fabricated a new narrative.
After all, discarding their own Mother Goddess was somewhat shameful even for gods focused on pleasure and benefit.
Unaware of the conflict between Tiamat and the primordial gods, the naive Ereshkigal simply thought the Primordial Mother had escaped the Sea of Imaginary Numbers. Overjoyed, she even wanted to share the good news with the other gods.
Of course, Ryuya stopped her.
Identifying himself as Tiamat's husband, Ryuya told Ereshkigal they were preparing a surprise for the gods and asked her to temporarily conceal their presence.
Because the Underworld was unique and unobservable by the other gods, and because the naive Ereshkigal agreed to help Ryuya and Tiamat prepare the 'surprise', their presence remained undetected.
Living in the Underworld, observing Ereshkigal, and learning about the current Uruk Era, Ryuya found Ereshkigal's personality very similar to the kind goddess from the Absolute Demonic Front.
As time passed spent together with Ereshkigal and Tiamat, he also learned the specific situation on the land of Mesopotamia.