TV-Series
Description
Ryujin is a powerful deity who serves as the guardian of the Dragon Orb. This divine being is deeply connected to Princess Kaguya, the ruler of the moon, as he was the one who defeated and sealed her away a thousand years ago to protect the Earth. For a millennium, Ryujin awaited a worthy human to wield the power of the Dragon Orb, and he established a series of trials to test any who sought it.

The personality of Ryujin is depicted as enigmatic and mysterious, making it difficult to determine whether he is a friend or an enemy to those who encounter him. He is a solemn and ancient being whose perspective operates on a different level than ordinary people, which can make his actions and intentions seem unfathomizable. Despite his ambiguous nature, he ultimately plays the role of a guardian and a benefactor, acting as a Big Good figure within the story.

Ryujin's primary motivation is to protect the Earth from the threat of Kaguya, the moon empress who seeks to conquer the planet. To this end, he created the Dragon Orb and hid it within the crater of Mount Fuji, ensuring that only a true samurai who could pass his rigorous trials would be able to claim its power and use it to combat evil. His actions are driven by a long-standing duty to maintain balance and prevent the return of Kaguya.

In the story, Ryujin plays the critical role of a mentor and a gatekeeper for the protagonist, Yaiba Kurogane. After Yaiba collects the six other legendary orbs, he is directed to Mount Fuji to undergo the trials set by Ryujin to obtain the ultimate Dragon Orb. These trials test not only strength but also the character and spirit of the challenger. Upon obtaining the orb, Yaiba is able to transform the Raijin Sword into the far more powerful Ryujin Sword, gaining abilities that include flight and a powerful energy shield. After Yaiba successfully uses this power to defeat Kaguya, Ryujin reclaims the Dragon Orb and disappears, his ancient duty finally fulfilled.

Ryujin has a significant and direct relationship with Princess Kaguya, who is described as his evil counterpart. A thousand years before the main events of the series, he fought against her invasion of Japan, defeated her, and sealed her away. This act established him as the primary force opposing her conquest of Earth. His other key relationship is with the Dragon Maiden, a priestess who serves as a key to unleashing Kaguya's true form. Sayaka Mine is revealed to be the descendant of this priestly line, and Kaguya specifically needs her essence to break the seal. While Ryujin does not directly interact with Sayaka, her lineage is intrinsically linked to his past battle with Kaguya.

Ryujin himself does not undergo personal development as a character, as he is a static and ancient deity. However, his legacy is central to the development of Yaiba. By overcoming the trials Ryujin set, Yaiba matures as a warrior and gains the immense power needed to face the moon people. Furthermore, Ryujin's death, which occurs during the series, has a profound impact on Yaiba, sending him into an unstoppable rage.

As a deity, Ryujin possesses formidable and legendary powers. His primary ability is control over the Dragon Orb, which contains and amplifies the powers of the six other orbs, including those of Water, Fire, Ice, Darkness, Metamorphosis, and Enlargement. When this orb is activated, it grants the user the ability to fly, create an invincible energy barrier, summon a dragon avatar, and unleash a powerful energy blast capable of destroying the Earth at full power. Ryujin himself was seen wielding a typical katana rather than the Ryujin Sword, suggesting his own inherent power does not require the magical blade. His ultimate feat of power was defeating and sealing Princess Kaguya, a being who can erase mountains with her ki blasts, demonstrating his status as one of the most powerful entities in the series.