Perhaps Yingdalan forces can steal
Iwanami Masayori's armor as spoils of war, returning it only a few decades after the Empire falls and the Crownlands are restored
EDIT: I have a (very,
very dramatic) idea. Any criticism is understandable.
In the mountainside of Fujiramoto (Berchtesgaden's equivalent) near the end of the war, Tanigawa is hanging out at his villa when suddenly enemy airborne troops drop in the place. He flees to Fujiramoto Shrine with a few surviving soldiers and his government body guards, heads for the inner sanctum where the armor is stored, and writes his death poem having put on Iwanami's original armor. As the enemy closes in, Tanigawa dons his helmet, charges the enemy under a hail of bullets from both sides with nothing but a katana (
bushidō s**t) and promptly gets shot in the chest and killed along with the rest of the Imperial forces. The enemy troops strip the armor off of his dead body and throw the latter in a nearby stream, never to be seen again.