Yarno the Blue,or simply Yarno,is a citizen of the Comfy Kingdom. Yarno tells you that he is the adviser to King Pin, although Button Boy, who comes right after, will tell you that Yarno is lying, and that he is the real advisor.
Spoiler: Who's the advisor?
If you give a small amount of money to Boots the cat, he will find Yarno for you, which will result in Button Boy thanking you. Later, after Pia, the adviser to the Celestial Kingdom, will offer you the chance to join the Council of Crowns. When you are accepted, Yarno will vote to support you as a candidate, and says that he told you he was the advisor.