The person behind it is Lysandre! Of course you wouldve known it because its on the story tags. The reason why Arceus is here is because how the fuck Xerneas would heal him? Like look. His intestines are damaged badly ok? Badly. He also have a massive blood loss because of that! Now unto the story.
Ash can see his blood spreading to the floor and he now realized that it was his final breath. As soon he passed out he seen himself in a place where theres nothing but white light. The second time he blinks he is now with Xerneas. Ash couldn't believe it. He rubbed his eyes to see if it was real. As soon he opened his eyes, he saw Arceus right next to Xerneas. Ash didnt know why the Kalos Legendary, Xerneas where there for him.
Meanwhile on the real world, Alola.
Two people are traveling to the Power Plant to see its demolition. As soon both of them were there, they were shocked. A dead body, Heavily bleeding which caused an extreme blood loss. Those two people were Kiawe and Sophocles. They ran back to the professor of the Pokemon School who is Samson Oak who is the Owner of the Pokemon School. All three talked to each other from what they saw.
Back to where Ash is currently.
"Why are you here Xerneas?" Ash asked. Xerneas replied. "I am here because i cannot heal you by my own." "And you Arceus?" Ash asked to the other one too. "The same answer, but." Arceys replied. "But, now what?" Ash questioned. "You have to stay with us until your friends are gone. Do you accept? When you come back alive instantly you would be killed again and you will never return, because we have to create energy to heal you. You see, when people who i chose never last long hear because when a person, just like you turn into Pokemon in 30 days. Do you want to wait until they are gone? Or you will come back again instantly." Ash replied "I choose to stay with you until my friends are gone." "Good Choice!" Arceus replied happily. "Thanks for the choice, Ash, You can call me if whenever you are. I am always be there." Xerneas said. Ash said to himself "I will come back world. Prepare yourselves."
Fast Foward to a couple of days later.
"Ash." Arceus called. "What?" Ash said to Arceus.
"Your friends are gone and we havee to bring you back to life. Your new name is Shijoro Izaka, to avoid for you to die again and train your Pokemon." Arceus said to Ash. "How would i revived?" Ash asked. "We will give our energy to you and get the normal blood capacity. Thats how you be revived. Oh and Hoopa will help you escape your grave also, leaving no trace to your escape." Arceus answered. "Hoopa is here." Arceus said. "Ashkun! Ashkun!" Hoopa happily calling Ash's name. "Hoopa! Im glad to see you!" Ash said "Me too!"
AN: Read this please. Next chapter we will skip the reviving process okay? Next time!