Who is Old Gentleman from The Big Wave and what is their importance?

The Old Gentleman lives in the castle on the hill. Before the big wave strikes, he rings the bell to invite the villagers to take shelter within the castle walls. After the death of Jiya's parents, the Old Gentleman wants to adopt Jiya as his son. Jiya, however, refuses because he has a home with Kino's family. The Old Gentleman allows the orphans to live in the castle outhouses after the big wave, but he thinks they are foolish for rebuilding the village on the beach many years later.