Ash's past life, becoming an Aura Master, understanding his persona, training from the god, and separation from the two forms.
In the Sinnoh region of the world of Pokémon, 15 year old Ash Ketchum travels towards Sunnyshore city for his 8th badge to enter the Lilly of the Valley conference on Lilly of the Valley Island. Currently traveling with him are Dawn and Brock, his two companions from the entire region. The gang was heading over to Lake Valerd to watch Dawn perform in the Grand festival. Unknown to the two companions, Ash carries a secret that no one has ever looked at before. The ability to go between worlds and understand Pokémon like no other human from before was bestowed upon him by one Pokémon that only Ash knew of while others were still confused of his existence. That Pokémon is Arceus, the God of Life and the Alpha Pokémon. Ash remembers everything that has happened with his past. This is how it happened.
Flashback 5 years ago
Ten year old Ash Ketchum was walking down a dirt path after saving Pikachu from a flock of Spearow. While they went over to Viridian city, a bright light blocked their path and absorbed them inside the vortex that appeared after the initial light show. Ash was confused with what is going on right now. He was walking down the main path without worry after escaping from the Spearow, and narrowly getting away from a certain redhead with a short temper, until this has happened. He and Pikachu blacks out due to the light show during the transfer.
Ash wakes up with a bit of a head ache after the transfer between worlds. He looks around to find himself in a divine temple of sorts and notices that the structure is all white with tinges of gold coloration on the edges of the pillars and walls. He hears a voice and turns to the source to find a gigantic figure stand in front of him with an aura of power. He quickly kneels before the god Pokémon, not knowing of the god's intuition or pleas to him. He heard the god say, "Arise, young Ash. I am Arceus, the Alpha Pokémon. I have called you to our world to ask you for your help." Ash was stunned. Not only did the god say that he was the legendary Arceus, but also that he was asked for his help. But questions came later. He wants to know what the legendary god wants of him.
He asks, "What is it that you wish to ask me of, my lord Arceus?" Arceus smiles, "Understanding of the legends' ranks and loyalties. Very wise. I called upon you to help stop a group of Pokémon called Omega. This group wishes to take over both of our worlds for their own will and destruction. I have chosen you to become an aura master." Ash asks, "Aura master?" Arceus nods, "Yes. I have chosen you for that title to help keep both worlds at peace from all criminal organizations from their own destructive dreams and tools of destruction. Do you accept this?"
Ash thought hard. He was given a title to bear for a very big price. He loved Pokémon and wanted to become a trainer to help people out from destruction and lead them down a path of righteousness, but given a title to protect both worlds between himself and the Pokémon of the world he is in right now. He thought of the opportunities that this will give him. He looks at the god with determination in his eyes and nods saying, "I do accept this title, my lord."
Arceus smiles, "Thank you. For this, I will transform you into a Pokémon that will help you out with your aura training between our worlds. Are you ready?" Ash nods again and closes his eyes. Arceus begins to glow and focuses on Ash, transforming him into a Pokémon that has very good mastery over aura. As he was about to deliver the form, Mew bursts in and causes Arceus to jump in shock and fire it into Ash's body like he planned, but with a problem that forces him to figure out about the transformations completion being 75% complete. He yells, "MEW! LEAVE US NOW!" Mew nods in fear and knew what was wrong, leaving in shame and knowing that she was in trouble. Arceus looks at Ash's new form, ready to tell him about his form.
Ash opens his eyes and notices Arceus staring down at him with an expression that he could not read. When he was about to ask, he felt something bounce on his chest. Curious, he looks down and notices white fur on his chest. But what he notices next forced him to scream in horror. He was a female Lucario.
Arceus creates a mirror for Ash to use. Ash looks into the mirror and studies his, now her, new body. She notices that she is an anthro female Lucario with a busty hourglass figure. She rubs her paw-like hands on her right leg and finds out about her feminine legs. She looks down at her feet and notices pink pads on her feet and figures that all canine Pokémon are like her. She lowers her legs and places her hands on her hips, noticing how wide they are right now. She moves her hands towards her back side and places them on her rump, surprised at how big it is. She even felt a long tail above her ass and that her fur was as smooth as silk. She looks at her arms and notices that they are not only slender like the rest of her body, but is also bulked up with huge amounts of muscle that is mainly used in fighting types. She looks down at her front and notices her breasts. Her breasts are so big, giving her busty figure a sense of beauty with her white fur. The size of her breasts are exactly an M-cup size. She blushes at the size and also blushes even further when she moves her hand down towards her lower torso. When she puts her hand at the underside portion of her front between her legs, she felt her vagina. She uses her other hand to squeeze her right breast and moans at the feelings she was getting. She shook her head and moves her hands from her private areas and looks at her face. Her mouth grew a muzzle with her mouth located at the bottom of the snout. She has 4 dreadlocks and her eyes are now a shiny orange color with eye lashes for most women. Her fur is a shiny white with long white hair. She was so beautiful, any male, including Arceus himself, would fall for her beauty. She punches the mirror with surprising force that shattered the reflective metal and breaks the material behind it, proving that not only she is showing her beauty, but also her strength and speed.
She screams at Arceus, "My lord, WHAT HAS HAPPENED?!" Arceus replies, "I-I don't know! I had the requirements exactly right at first and made sure that you should be a male still, but Mew came and disturbed me, lowering the transformation completion rate to 75% and making it incomplete!" Ash screams, "CAN YOU CHANGE ME BACK?! THIS IS EMBARASSING!" Arceus said, "Until the transformation is complete, there is no way we can change it. But don't worry. You are going to be in this form only in this world." Ash sighs in relief and says, "Ok. I understand. I will try to get over this and aid you in keeping the worlds in balance and out of the criminals' hands." Arceus smiles, "Thank you, Ash. And from now on, in this form, you will be known as Satoko. Here is a device that will allow you to switch between our worlds and train with your newfound abilities." Ash, now called Satoko, nods, "Thank you my lord."
End flashback
Since that day, Ash was training in private with his newfound abilities and switched between the two worlds at night. His persona, Satoko, was able to be more aware and instinctive than his original self. But due to his friends and the constant traveling that he was undergoing, he couldn't keep up with his training. At the beginning of his Sinnoh travels, his persona now had a fully developed aura that was separated from his own and made her his sister. He remembers what she told him at the night that they separated their aura and she was born.
Flashback 1 year ago
Ash was about to teleport into the Pokémon world until he fainted in mid transfer. When he woke up, he was in the same room that he met his lord and master Arceus. He looks to his left and finds his persona asleep. He touches her slightly and she moans, waking up from her slumber. She looks at him and asks, "Where are we?" He answers, "We are in lord Arceus' throne room. We must have separated from each other." Satoko nods, "If we are, then what do we do now?" Right after she said that question, a letter fell out of the sky and into Ash's hand. He read, "Ash and Satoko, I am in a meeting right now and I will arrive within 5 hours after the meeting finishes. Take this time to understand each other. Your lord, Arceus."
Ash and Satoko looks at each other and they knew what Arceus was saying. Ash says, "Let's try to remember about our pasts and times we had together, shall we?" Satoko smiles, "You bet, Ash. Since we are separated, we must be brother and sister now, don't you think?" He nods, "I sure do. Since this happened, you must have all of the memories from the Pokémon world while I have them memories from the main world, these stories should keep us entertained." His persona nods and the two began chatting about their past.
As the two passed the time with their stories for the next 5 hours, Ash began to understand his persona a whole lot more than he thought he did before. Satoko was the same with Ash as he was telling his stories about the normal world. The vast information that the two personas were learning from each other was giving them knowledge and understanding about their lives. As Ash was finishing his story about the battle frontier challenge, Arceus appears between them. The two bows down to him as he approached them. He spoke, "Arise, Ash and Satoko. I have called the two of you for something important." Ash asks, "What is it, sir?" Arceus spoke, "I am separating the two of you due to the lack of training that was forced upon the two of you." The two personas knew why. They nod, but Satoko asks, "How will we keep in contact with each other? When do we get to be together again? And how will we get our training done while separated?" Arceus spoke, "The two of you will stay in contact once a week in your dreams. You will be together again when a criminal organization, Team Galactic, will try to complete their latest plan, but Ash will stop. As for training, I will train you both in the ways of the aura. Ash, your training will be continued during the day with Sir Aaron's Lucario while Satoko will try to learn moves in her world." The two personas nod and just look at each other one last time before embracing each other before disappearing into their home worlds.
End flashback
The two personas were training, day in and day out, working hard on their aura control mastery until they rejoin each other again. Ash was developing a bond with her and for some odd reason; he was feeling a warm residence in his soul for his feelings with Satoko. Satoko was the same and was having a hard time on training. Ash and Lucario trained with superb timing in the evening, ignoring the stares of his friends and foes until the right time. He swore that once he destroyed all of the criminals, he will return to Satoko, declare his love for her, and stand by Arceus' side as a guardian. Satoko took the same swear and Arceus accepted the two's declaration. Soon, when the criminals join up in one cause, the two personas/siblings/lovers will be together again.