Symbol in the Fog

Exploration Stage: Pagoda of Legends
From: Yui
Description: Monsters will soon be flooding the streets! We should hurry and come up with a defense strategy. The Chinese treatises will help us. One of them mentions a Rocket Cannon. Will you look for it?
Completed: I read about the use of rocket cannons in a treatise by Ho Long Jing when I was preparing for battles. We can use the cannon to signal to each other when the monsters come.