Now that you have control of セシル (Cecil), I have a little assignment of my own as we’ll explore the castle a bit further.
Since we’ve been there a little while now, let’s leave the second floor. Head south and leave the current screen you are on to reach to first floor.

click to enlarge
You will then reach the first floor of the castle. If you look on your map, you’ll see three chests on the right side and this is where you want to go for now.
When you get there you will find a soldier standing guard next to three chests (press the switch to open the passageway to the chests). Most importantly, talk to this guard and pay close attention to what he says, in particular the two Kanji highlighted below:

click to enlarge
Now in order to understand the structure of Kanji, I will magnify each Kanji to allow you to see in greater detail what each one of them is made of: