Knowledge.

Atsuji Kurogame smiled at Yang Dao as the boy asked for his guidance. The old man said in a low voice, "It will be my pleasure and honor to guide you, young master." with that said, he featured the boy to follow him. 

Even if the two people had a servant-master relationship. Yang Dao treated himself below Atsuji at this moment. When he was in the orphanage, facing the harsh cold winds of life, he realized that you can learn about everything from everywhere and from everyone, only if you have an open mindset about it. 

This moment was the same. He was seeking guidance from Atsuji Kurogame, an elder. He followed him half a step behind him. The elder pulled him by his hand and said, "Even if you are a student, you can walk beside me."