Urobe was a son of the great chief of Pyrimi, Africa. One day he hanged on an airplane and came to Japan. Because of the cold and hunger, he fell on to the yard of Shishio’s house, and Shishio nursed him. Kurobe was very thankful for him and began to repay for his kindness. Kurobe dig a big hole in the yard Every time he return the favor, he threw a stone into the hole until stones would fill the hole.

(Source: Anime News Network)