As Acerola explained, Yuga finally understood what she meant.
According to Acerola, the Ghost World had two negative realms.
One was the Distortion World governed by Giratina, and the other was the Ghost World.
The Distortion World was a reflection of the real world, existing solely to correct the various errors in the real world, such as pollution or breaches, which required the Distortion World's intervention.
The Distortion World and the real world were interdependent, and if the Distortion World suffered damage, the real world would crumble as well. That's why, aside from Giratina, there were no other inhabitants in the Distortion World.
However, the Ghost World was different; it was the realm of ghosts and Specter.
At this point, Yuga realized that there were indeed Specter in the world.
People and Pokémon from the Pokémon World automatically entered the Ghost World when they passed away, becoming Specter inside it.
Of course, the Ghost World was different from the underworld of Yuga's past life; the Specter that entered didn't go through reincarnation. Instead, they became unconscious, drifting souls that gradually dissipated.
Some of them might, due to special circumstances, transform into Ghost-type Pokémon and continue living in the Ghost World, constituting another type of resident - the Specter.
If the Distortion World was responsible for correcting the real world's existence, then the Ghost World served as a containment for things that the real world shouldn't allow, such as Specters.
However, unlike the completely sealed state of the Distortion World, the Ghost World was in a semi-closed state.
Connecting the Ghost World and the real world involved a special type of Pokémon - the Dusknoir, and special humans - the Ghost World Emissaries.
Dusknoir had the ability to link with the Ghost World and carry humans into it, as rumored.
However, not all Dusknoir possessed this ability. Only those born in the Ghost World could do so, while all ghost-type Pokémon in the real world couldn't.
Ghost-type Pokémon in the real world could increase their numbers through breeding, but Ghost World's ghost-type Pokémon were different; they couldn't reproduce and could only increase their companions through conversion of Specters.
Next was the Ghost World Emissaries.
As mentioned earlier, there was no concept of reincarnation for the Specter in the Ghost World. However, there was one exception - the Ghost World Emissaries.
They were originally Specter in the Ghost World, but after being selected by the Ghost World's consciousness, they would be sent back to the real world to serve as Ghost World Emissaries.
In other words, Ghost World Emissaries retained some memories from their past lives.
Ghost World Emissaries were extremely rare, with at most one appearing on each continent. Their mission was to guide Specter into the Ghost World.
Of course, since there were so few Ghost World Emissaries, it was impossible for them to guide all the Specter from the entire continent. Given the unknown number of deaths among humans and Pokémon every day, they couldn't keep up.
As long as there were no unexpected circumstances, the souls of humans and Pokémon would automatically enter the Ghost World after death, and there was no need to worry about it.
Ghost World Emissaries were responsible for those Specter who, due to special reasons, couldn't or wouldn't go to the Ghost World.
And Acerola was one such Ghost World Emissary. That's why she called herself "half from the Ghost World."
She truly originated from the Ghost World but had become a genuine human, no longer a Specter belonging to the Ghost World.
Even though the Specter in the Ghost World, even if unconscious, possessed some special abilities, making them very close to ghost-type Pokémon, the moment Ghost World Emissaries awakened as humans, their special abilities would disappear, leaving only the ability to be close to ghost-type Pokémon.
Of course, it wasn't a complete loss; some of them could still communicate with ghost-type Pokémon.
Each Ghost World Emissary had a special Dusknoir as a partner, helping them carry out their task of guiding Specter.
And among them, there was a special existence - Cecilia.
Strictly speaking, Cecilia isn't truly a Ghost World Emissary because she hasn't become a human; she remains in a state of a Specter.
Ghost World Emissaries, as they transform from Specter into humans, experience the natural processes of life, including aging and death. Therefore, there is a need for substitute Ghost World Emissaries.
Cecilia is a substitute Ghost World Emissary.
As long as one Ghost World Emissary steps down from their role, she can smoothly take up the position of the next Ghost World Emissary.
However, she did something that led to the Ghost World consciousness revoking her position as a substitute Ghost World Emissary.
While Giratina, the ruler of the Distortion World, possessed its own consciousness, the Ghost World consciousness did not. It wasn't a living being but rather a set of rules, the fairest and most impartial rules, necessary for managing the Ghost World.
Any Specter or ghosts in the Ghost World that committed wrongdoings would face the Ghost World consciousness's most impartial punishment.
Cecilia impatiently took matters into her own hands, using the Specter in the Ghost World to create a physical body for herself, becoming a human. This caused a large number of Specter and ghosts in the Ghost World to dissipate.
Initially, she should have had her memories wiped by the Ghost World consciousness and returned to being an ordinary unconscious Specter. However, with the help of her Dusknoir, she managed to escape from the Ghost World and stole Acerola's Ghost World Flute.
Ghost World Emissaries, apart from their partner Dusknoir, who can help them open the Ghost World's gate to guide Specter, rely on their Ghost World Flute as proof of their identity.
That's why Acerola pursued Cecilia's trail so relentlessly.
After listening to Acerola's account, Yuga fell silent for a long time.
The world had so many secrets that he hadn't known about before.
Whether it was the Distortion World, the Ghost World, Dusknoir, or Ghost World Emissaries, Yuga found the world to be vast and truly remarkable.
But he hadn't anticipated just how dangerous Cecilia could be.
However, why did Cecilia take such actions?
As long as she waited for the previous Ghost World Emissary to step down, she could have legitimately and risk-free transformed into a human. Why was she in such a hurry?
Acerola looked at the silent Yuga and asked, "So, can you tell me where Cecilia has gone now?"
Yuga, regaining his composure, smiled and said, "Actually, she has already returned to the Ghost World!"
"Returned to the Ghost World? That's impossible!" Acerola exclaimed.
She knew that the Ghost World consciousness was waiting for Cecilia's return. Her fate upon returning was to have her memories wiped, becoming an ordinary Specter, forever remaining in the Ghost World until she naturally dissipated.
"It's like this..." Yuga proceeded to explain Cecilia's actions in capturing children in Verdanturf Town and her eventual return to the Ghost World with the help of her Dusknoir.
"I see," Acerola sighed. "Perhaps her Dusknoir didn't want to see her continue making mistakes."
"I've said everything I know. Cecilia probably won't return to the real world, right?" Yuga asked.
"Don't worry, she won't appear in the real world again," Acerola reassured him.
With that, Acerola stood up, sighed, and said, "Now that Cecilia has returned to the Ghost World, it's time for me to go back to Alola. Goodbye."
Yuga nodded and escorted Acerola out.