Who is Ignatius Small from The Cat Who Went Underground and what is their importance?

Ignatius Small, known as Iggy, is the second builder that Qwill hires to construct his addition. Gary Pratt recommends Iggy as lazy but a good craftsman. Iggy is described as an emaciated man with large teeth. He vanishes when Qwill is hospitalized, and with Koko's help, Qwill later finds Iggy buried in the crawlspace. Iggy is the fifth carpenter that Joanna kills.