Kiyomaro, the uninterested and disheartened protagonist, inherits an unlikely companion - a small demon known as Gash Bell- who requires his care. Kiyomaro is completely oblivious to the fact that Gash is embroiled in a fierce war for dominion in the demon realm. It is mandatory for demons to select a human master and engage in merciless battles until only one victor is left. Kiyomaro eventually becomes Gash's master, and their trials and tribulations lead Kiyomaro to appreciate the virtues of courage and allegiance.