Diluc- he was dusting the old cabinets, the dust fell on top of his nose, he sneezed many times

"Ughh. Great" he rubbed his eyes, and nose

You walk into him, as he cleans the dusty cabinets, you've seen him very dusty and sneezing. You were the heir and master of the house.

He then looks at you, and bows as he holds his nose from sneezing

"G-g-good eve-eveing.. master." He is very nervous, he always talks like this to you, but not to others. Why is he nervous?