The world has been in peace since the last war nearly 30 years ago, people like Lt. Surge are the few remaining veterans of that terrible war. Peace has made everyone too easy going, warnings from people like Surge go completely unheeded. Even with these warnings being ignored there seems to be no chance of war, small border disputes are quickly resolved by governments and peace upheld. That quickly changed over the course of a couple of months, the champion from Kanto accidentally harmed citizens from Hoenn. This happened around a time when ownership of the island was greatly contested between the Hoenn and Kanto governments already; Red apologized and the matter was largely solved. Not for the islanders who had been on the receiving end of the suffering, they demanded blood and when their government wouldn't do it they did. Forming a terrorist organization with the help of an old Team Aqua member; the new terrorist organization dubbed itself Team Resonance and demanded reparations from Kanto.
Kanto listens openly to the demands for a week before refusing communication with the group. This only brings Team Resonance the excuse to launch an attack, an expertly launched large scale bombing in Celadon and Viridian cities. The casualties of the attacks reach the thousands and tensions between Kanto and Hoenn mount; at this point Hoenn worried about war gets into contact with Sinnoh and requests a formal alliance.
Publicly Kanto and Hoenn attempt to lower tensions, behind the scenes mobilization begins and alliances are renewed. Hoenn and Sinnoh go into deep discussions about the prospect of alliance. Peace is still within reach but fading quickly, all it needs is one last push and war will begin.
Kanto forces Hoenn's hand only a week after the first terrorist attack. They send and ultimatum:
-OPEN-
To Hoenn Congress of Gyms,
We (The Kanto League) demand the following in exchange for continuing peace:
Stop Hoenn media from creating slanderous images of Kanto (Including but not limited to the people, government, and land)
Stop openly anti-Kanto groups from meeting
Eliminate from schools all works that slander Kanto
Remove the police, army, and government officials whose names we provide
Accept Kanto police forces (with full power) into Hoenn to search for terrorist cells
If these demands are not answered within three days of this being sent, our nations will enter a state of war.
-CLOSE-
This document immediately outrages the Hoenn government for a number of reasons. The two most glaring were the removal of officials at Kanto's demand and allowing Kanto police free reign inside their country. A few Kanto and Hoenn officials get their two champions to meet in hopes that they will be able to help their nations through this without causing a war. That hope is lost when through simple miscommunication the two champions end up in opposite parts of the world from eachother. Hoenn waits, at the end of the three days at the last possible moment they send their one word reply "No" and so the two nations are at war.
Thank you for reading the first part of this- truth be told I don't know how to continue from here the way I see it there are a few ways:
Continue in narrative mode, viewing everything and chronicling the war
Take the perspective of a grunt (maybe a squad or pokemon?)
Take the perspective of an officer, looking at maps and deciding how best to handle situations
Take the perspective of a gym leader, champion, or other skillful trainer
Take the perspective of a generic "Black dog" character, someone who until the war broke out was just thought to be average but shows extreme talent stronger than almost anyone else (becoming stronger as needed via plot armor)
If you would pick one of those 5 for the continuation of this I would be happy, as it stands I cannot continue writing.