Pokemon One-Shots and Headcanons

Death

Set 4 years after the events of XYZ. Follows canon for the most part, although I'm ignoring Ash's Alola friends.

Nurse Joy looked sadly at the young black-haired man lying unconscious on the bed in front of her. Despite her best treatments, she had failed. Ash Ketchum was dying, from a mysterious illness that no one had been able to identify. At first it had started out as a small cough, but then had quickly worsened, until he had actually been coughing up blood. He had started hallucinating as well and suffered random seizures. No matter what anyone did, though, he hadn't shown any signs of improvement. And now his life was draining away slowly, each heartbeat growing steadily fainter than the last.
"Ash, I'm so sorry," Nurse Joy whispered. "I failed you."
"Pika..." Pikachu whispered, staring miserably at his best friend.
She watched, tears rolling down her cheeks, as the monitor gave one last beep before going silent. Pikachu screamed, but somehow it did little to break the agonizing silence that filled the room. Ash Satoshi Ketchum, the savior of Kalos, was dead.

At Professor Oak's ranch:

All of Ash's Pokemon were playing happily when Professor Oak approached them, his face grim and his eyes sympathetic. Sensing that something was wrong, Charizard walked up to the aging professor and looked at him curiously. They exchanged words for a few minutes before Charizard turned around again, pale and shaking.
"What's wrong, Charizard?" Sceptile asked anxiously.
"Ash..." the fire-type whispered.
"What about Ash? What happened?" Hawlucha asked.
"He-he-" Charizard muttered, unable to tell his friends the horrible truth.
"He what? Charizard, he WHAT?!" Noivern screamed at him. At that, Charizard finally snapped.
"He's dead!" he shouted. "All right? He's dead!"
The other Pokémon stumbled back, not wanting to believe it.
This wasn't happening. This simply wasn't happening.
How could Ash be dead?

In Cerulean City:

Misty Waterflower was busy training her Pokemon when her oldest sister, Daisy, entered the training arena with a somber look on her face. She knew immediately something must have happened. Her sisters never spoke to her willingly unless it was to insult her, and somehow she didn't think Daisy was here for that purpose.
"Misty, I'm so sorry," Daisy said sorrowfully. Now Misty was frightened. Her sisters definitely never apologized to her for anything.
"For what? What happened?" she asked fearfully.
"It's Ash, Mist. He's gone," Daisy said sadly. Misty stared at her sister in shock and horror.
Gone...no, he can't be gone. This is all some sort of joke, she thought desperately.
"Please tell me you're joking, Daisy," she whispered.
"I'm sorry Mist, I wish I was," her sister said quietly. "I'll leave you alone for now if you'd like. You can talk to any of us whenever you want."
"NO! He's not dead! You're lying to me!" Misty screamed. Her Pokemon all cowered in fear, but she didn't care. "Ash is okay! He's perfectly okay and will become a Pokemon master! He-is-not-dead!"
Unsure what else to do, Daisy did something she hadn't done in years and put her arms around her little sister. Misty buried her face in her shoulder, sobs shaking her body.
"He can't be dead...he just can't be," she whispered.

In Pewter City:

Brock couldn't believe it when he heard the news. How could Ash, lively, spirited Ash, the Ash that was courageous to the point of recklessness, be dead? It just didn't make sense. It made so little sense to Brock that he couldn't even cry, for there was a part of him that insisted that this was all a joke and that his friend was still alive and well somewhere, continuing on his journey to becoming a Pokemon master.
But at the same time, he knew this couldn't be a joke. Why would anyone joke about something like this? It would be beyond cruel. So Brock had no choice but to accept the fact that his friend was gone.

In Hoenn:

Max Maple was playing with Gallade when his sister, May, walked into his room with tears streaming down her face.
"May, what's wrong?" he asked worriedly. He hadn't seen his sister this upset for a long time.
"Ash is dead," May whispered. Max reeled back, certain he'd heard wrong.
"What?" he whispered.
"Ash is d-dead," May hiccuped, a little louder this time. "They say...he was sick...didn't know what it was...couldn't do anything to save him..."
Max stared at his sister, disbelief coursing through him. Ash was dead. His longtime hero was dead.
This wasn't possible. How could it be possible?
But it was.
Time seemed to stand still for a moment as the truth sunk in.
Then, before he knew it, Max keeled over and fainted.

In Sinnoh:

No, no, he's not dead! This isn't happening! My best friend is not dead! He's not...how? How could this have happened? How could he have gotten so sick? Why couldn't they find a cure? Dawn thought in agony, screaming as she punched her bedroom wall.
I don't believe this. I don't want to believe this. He'll come back. I'll see him again soon. I have to believe that...have to...believe...
Dawn slumped to the floor, crying uncontrollably. Ash was gone. What was there left to believe in?

In Unova:

Iris couldn't stop crying when she heard the news. Her little brother was gone. Because of a stupid illness that no one could cure. It was just so unfair. Cilan tried to comfort her, but he could do little when his pain was just as great as hers.
"Oh, look what we have here. The pathetic little dragon master," sneered a familiar voice. "Are you crying?"
Pure rage erupted inside the budding dragon master. "Shut up, you bitch!" she roared, slapping a shocked Georgia across the face as hard as she could. "I don't have time for you right now! Ash is-is dead and you have the nerve to come up to me and start mocking me like-like-ugh, you are so inhuman!"
Georgia stared at her rival in shock. "W-what?" she whispered finally. "Ash is...gone?"
Iris glared at her. "Yes, he's gone, you idiot!" she screamed. "I just told you that! Now get out of here and leave us alone!"
She turned away after that, neither knowing nor caring if Georgia had complied.

In Lumiose City:

Bonnie and Serena, who was visiting from Vaneville Town, were watching Delphox, Sylveon, and Pancham (I didn't have Pancham evolve since I don't think Pangoro would be suited for the types of performances Serena gives) playing together when Clemont approached them, tears in his eyes. The girls jumped up, worried at seeing their friend and brother so upset.
"Clemont, what's wrong?" Serena asked anxiously.
"Ash," Clemont said shakily. "He-he's dead. He was sick and they couldn't cure him-they don't even know what he had."
The girls stared at him, pure shock and horror on their faces. Then Bonnie fainted and Serena started screaming and crying.
"No, no no! This can't be happening! Please tell me this isn't happening!" she screamed. Clemont gently placed his arms around her as she cried into his shoulder.
"I'm sorry, Serena. They did everything they could, but he just wasn't getting better," the Lumiose gym leader said sadly.
"I loved him," Serena whispered. "I know everybody thinks it was just a crush, but it wasn't. I really did love him."
Clemont didn't know what to say to that. He just held his second sister close and let her cry. Suddenly, another thought seemed to cross Serena's mind.
"Clemont...what will happen to Ash's Pokemon?" she asked.
"I don't know," Clemont admitted, frowning. "I suppose they'll just go wherever they want to go."
"I'm going to take them in," Serena declared.
"Are you sure, Serena? I mean, it's a big responsibility," Clemont cautioned her.
"I don't care. I need to do this. They're all I have left of Ash besides you and Bonnie....I have to do this."

With Squishy, Z-2, and Greninja:

Greninja was sitting with his friends when he suddenly felt a sense of cold emptiness inside him. He didn't have to guess what was happening. His connection with Ash had disappeared. Which meant that Ash was...was dead.
"No..." he choked out. Please, no. Please let this all be a nightmare.
"What's wrong, Greninja?" Squishy asked.
"I can't feel Ash anymore!" Greninja practically screamed. "The connection...it's just gone! He's not there!"
"Calm down," Z-2 said soothingly. "Maybe he's just too far away. I mean, we don't know where Ash went. The connection could be affected by distance."
Greninja wanted desperately to believe that was true. But still, a voice in his head reminded him that the connection had never wavered once throughout the four years they'd been apart. It had always been there, stronger than ever, just like Ash promised it would. If it wasn't there now, then the only possible explanation was that Ash was gone.
His body wracked with pain, Greninja walked away from his friends and sat down alone by the river and cried.