The serpent seems so indifferent towards him that it's just sad 
As of now it seems that he is being polite but he doesn't really care about him
Spoiler!
Underrated manhwas I recommend:
1. The Foul
2. No Moral (novel as well)
3. Circumstances of fallen lord (novel&manhwa)
4. I'll raise you well in this life
5. One roof two strangers