Rolwoy (ロルウイ, roruui) is a demon appearing in the series.
Roluwi is an Australian Aboriginal spirit encountered in the legends of the Jiman/Yiman people of northeast Australia. He stands between men and gods, but his appearance is mostly that of a youth. According to legend, a long time ago yamuimo (potatoes) walked around freely. It seems that this aimless wandering of yamuimo destroyed people's long-awaited crops and gave them a lot of trouble. That is when Roluwi showed up and chastised them, ordering them to go back into the earth and stay there like yamuimo are supposed to. His harsh behavior is what helped people, whose crops got better and daily life prospered.
"An Aboriginal fairy that looks like a young man wearing a dark apron with four yam leaves on each limb. One day, he saw a yam walking through the jungle and told it to stay put in the ground. The yam did what it was told, and that is why yams are found in the jungle today."