"Where were we again?" He briefly glanced at the three dead Homunculi, then at Nysa. "Oh right, Asteri's true nature."
"Are the Henosis Seekers searching for her?" Nysa asked while following his cue to leave the area.
Jonam casually led the way. "I must've said it wrong. It would be more accurate to say that she's a product of the Henosis Seekers' presence here, as well as what I assume to be a necessary step for their end goal."
He hopped over the destroyed tower ruins before skirting around the water stream. "I assume you're aware of the three classifications of occult creatures in the magus world? Eidolons, Dead Spirits, and Natural Spirits... Though there's some debate currently about whether or not to include Sea Monsters among these categories, too."
"I asked for explanations, not a lecture," Nysa said.
Jonam answered with a smile. "It's a force of habit. I'm sorry, truly. Anyhow, when a person dies, their thoughts and consciousness leave an echo in the flow of Mana—a legacy of a lifetime's worth of emotions, dreams, and ambitions. Typically, this echo would dissipate shortly after their passing, and their soul would peacefully head to the Netherworld."
"However, in the case of individuals with particularly strong drives, this echo would persist even long after death. It's especially true for humans with deep regrets or unfulfilled goals. As this part of themselves, reflected through Mana, continues to subsist in this realm, it chains down their souls and twists their minds, leading to the birth of a Dead Spirit."
Jonam's blue eyes shone through the night, surveying their surroundings as they walked.
"Now, let me ask you. Knowing that a Dead Spirit is basically a soul infected with the flow of Mana's inherent madness, what would happen if it were to try and inhabit a vacant body?"
Nysa pinched her chin, deep in thought. "A soul making contact with Mana this way is akin to an Insight Ritual with no measures taken against madness. It'd be like directly looking inside the Reverse Boundary of the World. Should it successfully inhabit a body, it'd become—"
"—a magus, right." Jonam completed her sentence. "As a rule, Dead Spirits cannot inhabit a dead body that isn't their own. However..."
"Myrine Polycaste succeeded anyway," Nysa interjected.
"Not really. Seeing that you know her full name, I assume you were the one to kill Old Nestor. Poor man." Jonam shook his head. "Did you learn the girl's story?"
"Vaguely. The old man was too cowardly. He never reached out to her."
"Humans are complex creatures. I wouldn't exactly qualify him as cowardly, but we're straying from the subject. I presume you also learned of the fire that killed Myrine through his memories."
Nysa nodded. "Yes, although there was something strange. The girl in the old man's memories has bright green eyes, while Asteri has mismatched, brown-and-green eyes. Furthermore, when I spoke with her earlier, she described the fire and her own death as an observer, not as the one who suffered it."
Jonam slightly furrowed his eyebrows. "Did you not notice anything odd with the girl's appearance?"
"The spell allows me to gain an understanding of the old man's memories, not live them. I know she has bright green eyes because they left a deep impression on him, but I couldn't learn if there were other physical discrepancies."
"That explains it, then," he calmly said. "From my understanding, Myrine Polycaste had a slightly older sister named Asteri. She was the fruit of a night between her father and a prostitute, and he never recognized her. Myrine stumbled upon her one day while roaming the slums and came to that conclusion due to their extreme physical resemblance."
"While Myrine had a rough childhood, Asteri's was mired in the filth of brothels and sexual slavery. As sad as it sounds, they bonded over their misery and found in each other what they lacked from their respective parents and siblings."
Jonam sighed. "The person who watched Myrine burn alive was Asteri. The sight broke her mind so thoroughly that she took out her own life shortly after, still atop the spire. I do not know what emotion drove Myrine to become a Dead Spirit. Perhaps it was the hatred she felt towards her family, who so easily abandoned her, or the desire to pursue the happiness she had recently acquired with her sister."
"In any case, her Mana-twisted soul flew directly towards Asteri's corpse, who had just committed suicide."
"That's when she became the Asteri we know?" Nysa asked.
Jonam shook his head again. "I believe I told you she was human-engineered. Inhabiting a dead body that isn't hers is nearly impossible, and the initial attempt failed. That is until the Henosis Seekers found them."
He gestured for Nysa to take a turn, walking next to River Phanias. From this distance, they could clearly see the scorched building, the crooked spire, and the warehouse supposed to be the Henosis Seekers' hideout.
"They experimented on them, using obscure means to graft Myrine's Dead Spirit and Asteri's soul inside the latter's body."
"The constant friction between the two generates a mystical reaction that acts as a ritualistic sacrifice. Both sisters' very consciousnesses are chipped away little by little to fuel a particular spell, obliterating everything that constitutes them—memories, emotions, and sense of self. Ultimately, it will consume their existence, barring them from even knowing peace in the Netherworld."
Something tugged at Nysa's heart, but she ignored it. With a dismissive shake of her head, she asked, "What's this spell?"
"You've heard of the Pale Malady, I believe?"
"The sickness that's been spreading through the slums recently?" Nysa nodded. "From what I know, it's highly contagious and causes patches of pale-white feathers to grow inside the infected bodies. I've never seen it firsthand, however. Don't tell me... the Henosis Seekers are behind it?"
"Indeed." Jonam took the pouch attached to his belt, revealing the cracked, nearly completed orb inside. "This little stone is the most condensed form achievable of the Pale Malady. It's not an illness native to this realm. As you would expect, its manifestation requires an agonizing, ritualistic sacrifice directed at one of the entities worshipped by the Henosis Seekers."
"The ritual slowly destroys one's sanity and is relatively inefficient. At first, the Henosis Seekers were doing it themselves, kickstarting the illness' initial spread in the slums. But..."
Nysa frowned. "They found another method thanks to Myrine and Asteri."
"Sadly, yes. The suffering generated by grinding two souls together is the perfect offering for the twisted entity behind the Pale Malady. They don't care if it causes their entire existence to vanish afterward. Fueled by unfiltered agony, the spell would slowly solidify into these white stones inside the victim's body."
"Once completed, it would blow up, killing its tormented host and spreading the Malady to anyone in the vicinity."