Who is Mr. Hiram Otis?

Hiram Otis, patriarch of the Otis family, is presented by Wilde as being the quintessential American. Direct, outspoken, and down-to-earth, Mr. Otis has no time for anything that smacks of flim-flam. And flim-flam is precisely what he thinks this whole Canterville ghost business really is. Hiram is a resolutely practical man, who finds the whole notion of the supernatural to be so much nonsense.
Wilde uses the character of Mr. Otis to comic effect, highlighting the culture clash between the United States and old Europe. Otis is fiercely proud of his country's democratic heritage, which stands in stark contrast to the rigidly hierarchical class structure of British society, dominated as it is by an aristocratic elite. An illustration of this comes when Otis refuses to accept the Canterville jewels. Otis understands the importance of the jewels to the dignity of the English aristocracy, but as a firm believer in the values of republican simplicity, he cannot accept them. To him, they symbolize an effete, pleasure-loving aristocracy which is alien to traditional American values.

Mr. Hiram Otis is the father of the American family that rents Canterville Hall in England. Like the rest of his family, he is completely American. He definitely does not believe in ghosts, and when Sir Simon leaves a bloodstain by the fireplace, Mr. Otis is all for scrubbing it out using Paragon laundry detergent. Even when it becomes clear there is a ghost in the house, Mr. Otis is not afraid of it.
When his daughter Virginia wants to marry an English aristocrat, Mr. Otis is unimpressed. He also objects to her receiving the Canterville jewels as her reward for helping Sir Simon to his final rest. Aristocracy and jewels go against his sense of rugged democratic principles and the ideals of American simplicity. However, in the end, he gives in.