"Tenjin Kaisen" is a Gameboy title set during Japan's Shogunate period, roughly one hundred years prior. An oppressive entity known as the Lord of Darkness unleashes a fearsome army on Japan, spreading turmoil and devastation. Those who dared to resist were savagely eradicated. The formidable Shogun, Tokugawa, foresees the rise of a group of formidable warriors, who champion the cause of the suppressed. Assembling the five most courageous and talented fighters, he embarks on his quest to overthrow the harsh Lord, marking the unleashing of the Mercenary Force.
Over one hundred years ago during the mighty Shogun era, the Lord of Darkness sent his fearsome army to terrorize the Japanese countryside. Using the Dark Lord's powerful magic, his evil minions spread famine, plague, and pestilence wherever they went, leaving the peaceful population hopelessly oppressed. All who challenged the wicked Lord were mercilessly slain as a warning to all those who had any further thoughts of rebellion. Then one day while meditating, the great Shogun, Tokugawa, had a divine vision where he saw a small group of mighty warriors rise up to defeat the evil Lord. He immediately set out to recruit the five bravest and most skillful fighters in the land. After months of searching he was finally ready to put his dream into action. It was time to unleash the Mercenary Force.