Who is Okubata from The Makioka Sisters and what is their importance?

Okubata is the youngest son of a wealthy merchant. He eloped with Taeko when they were both very young. Okubata is described as a confident, young man, who likes nice clothes. Over the course of the novel, however, we learn that he is expelled from his family when it is discovered that he is stealing items from his family's jewelry store. It is later revealed that Taeko had known about the thefts. Okubata leaves Taeko when she becomes pregnant, and he blackmails Teinosuke to keep the matter secret.