Jiruo (known as Leader by his students) is a moon whistle Delver who serves as a teacher for apprentice delvers from the Belchero Orphanage in the town of Orth. While he works as an instructor for the children, he's also largely responsible for their upbringing and well-being.
White hair with bright blue eyes, average height.
As a teacher, he cares for all the students of Belchero Orphanage, ensuring the safety of all including bell-bearers, however, he is strict during night time patrols.
When he was at young age, he had already been a red whistle delver; he received from Lyza the duty to take care of her child, Riko. In Lyza's conversation with Ozen, Lyza said that she expected him to hide Riko's identity before her Last Dive into the Abyss.