Mr. Omer runs a clothing store in Yarmouth with a helpful sideline in undertaking. He prepares Mrs. Copperfield, David's little brother, and Mr. Barkis for burial. Mr. Omer is pretty much there as an Exposition Fairy. He flies into the novel to catch David up on what has been happening in his home town and in Yarmouth while David has been off at school or with Miss Betsey or in London. Then, Mr. Omer, flies out again.
Mr. Omer is also a useful plot device to show what everyone else in David's home town think of Emily. Mr. Omer takes Emily on as an apprentice dressmaker, and while Mr. Omer has nothing bad to say about her, he nevertheless conveys that Emily is not popular with the other women in town. Foreshadowing!