Dic in his house
Dic is the inventor that lives in the north-east house at Raejack Village. He will give the player the Dash Boots (free, instantly), and upgrade the Fire Shield to the Bolt Shield (1000G, then wait a while, as he invents rubber).
Game Reference[]
Dic is "Cid" spelled backwards, which makes a direct reference to the Final Fantasy series. Cid, in most of the Final Fantasy games, is often an inventor or engineer, much like the Dic we see here in 3D Dot Game Heroes.