He is the anime representation of the Jewish person of the same name. He was the father of Anne Frank, and the sole member of his family to survive the Holocaust. His full name is Otto Heinrich "Pim" Frank.

Otto Frank took his family into hiding on 6 July 1942 in the upper rear rooms of the Opekta premises on the Prinsengracht. They were joined a week later by Hermann van Pels and his wife and son, and in November by Fritz Pfeffer, also known in Anne's diary as Mr. Dussel. Their concealment was aided by Otto Frank's colleagues Johannes Kleiman, whom he had known since 1923, Miep Gies, Victor Kugler, and Bep Voskuijl.

They were concealed for two years, until they were betrayed by an anonymous informant in August 1944. Frank, his family, the four people he hid with, and Kugler and Kleiman were arrested by SS Officer Karl Silberbauer. After being imprisoned in Amsterdam, the Jewish prisoners were sent to the Dutch transit camp of Westerbork and finally to Auschwitz. It was here, in September, that Frank was separated forever from his wife and daughters. He was sent to the men's barracks and found himself in the sick barracks when he was liberated by Soviet troops on 27 January 1945. He travelled back to the Netherlands over the next six months and set about tracing his arrested family and friends. By the end of 1945, he knew he was the sole survivor of the family, and of those who had hidden in the house on the Prinsengracht.

Otto Frank passed away due to lung cancer on the 19 August, 1980.

Information taken from: http://en.wikipedia.org/wiki/Otto_Frank</a>