You don't even know what happened. First, Gensokyo opens to the real world, gaining its weaponry and technology, then the next moment full on trench warfare. Snice Damaku was impossible in the real world. All of Gensokyo now had to use guns and other things. The Great War gave the opportunity to Gensokyians to prove that they would hold strong against invaders. now here you are sitting in a trench with your Lee Enfield ready. Next to you, a familiar face. Reimu Hakurei. You both sat in silence as per order from your commanding officer.

"..." March of 1916, the battle of Verdun. You thought to yourself, then Reimu spoke up

"It's so quiet... too quiet."