Ryugan is an anime-only character of the Naruto anime and one of the antagonists of the final pre-Shippuden filler arc, the Seimei Revival Arc. He was one of the Four Celetials of the Village of Artisans who served under Hoki, being the youngest of the entire group.
Ryugan was born in the Village of Artisans and grew into a powerful shinobi who, wanting his village to rule over all other shinobi lands, joined the group called the Four Celestials under Hoki. To accomplish their goal, the group planned to use the chakra of Gaara's Tailed Beast, Shukaku, to help revive Seimei, the founder of their village, as the ultimate weapon.
Failed attempt at conquest and deathRyugan and his teammates arrived at the Hidden Sand Village, killing off all but one of the guards at the entrance to send a message to their target, Gaara, that they wanted to challenge him, threatening to take one person he cared for a day until he accepted. Scouting him out later with his student, Matsuri, Ryugan and his teammates took her hostage to ensure Gaara would accept their challenge, him wondering why he would care about a kid. Leaving behind Kujaku to have first shot at Gaara and his siblings, Ryugan confronted them next, engaging Kankuro, his brother, in battle. Using his Dark Fang Blade, Ryugan proved easily to be too powerful for Kankuro, shattering his Black Ant puppet to pieces and nearly killing him before reinforcements arrived from the Hidden Leaf. Despite being outnumbered four-on-one, Ryugan arrogantly claimed his sword should be able to handle them, growing increasingly angry and anooyed by them screwing up their fighting moves. When his leader, Hoki, signaled to him and the others, Ryugan and his teammates activated their Ninja Tool Barrier: Reverse Scale Formation and watered down Gaara's sand, making it useless(though this aspect was later rendered completely non-canon in the manga). Continuing his fight, Ryugan was fooled by his adversaries, Kiba Inuzuka, Choji Akimichi, and Kankuro distracting him while Akamaru, a ninja hound, rebuilt the Black Ant, allowing Kankuro to trap Ryugan inside and promptly kill him off with Secret Black Move: Iron Maiden.
Ryugan was just like his teammates in the respect that he was quite loyal to his village in his own way, despite not receiving any support from them at all, and was quite arrogant about his abilities, viewing his opponents as trash that had no chance of defeating him, and generally viewing battle as a game, traits that led to his demise.