Panther King

The Panther King was a powerful Daiyōkai and King of the Panther tribe. He was originally slain by Tōga decades ago. The Panther Devas hoped to revive him, but inadvertently sacrificed themselves to bring the demon back to life.

History
Two centuries prior to the point in the Feudal era that Kagome broke Inuyasha's seal, the Panther Devas invaded from the west and tried to conquer the lands in the east and subject all demons to their rule. To avoid the abominable effusion of blood — both human and demon alike — Tōga and the Panther King dueled one-on-one, with the former soundly defeating the latter to his death.

During the story
Two hundred years later, the Panther King's followers (possibly children, it's somewhat unclear) put into play a plot to bring the Panther King back to life using shards from the Shikon no Tama. They brought his mummified corpse to a secret castle town where they planned to revive him and, from there, finish the war they began long ago.

After awakening from his two-century sleep, the Panther King prepared to devour the villagers to complete his restoration, only to have Inuyasha thwart him from taking his sacrifices. Impatient with their attempts to provide him with "a life and a soul", he killed Karan, Shūran, and Shunran, and devoured their essences greedily, all while Tōran, who had narrowly evaded his attack, looked on in horror. With his body restored, the Panther King immediately took on Sesshōmaru and Inuyasha, the sons of his onetime rival. With power now greater than that of Ryūkotsusei, the Panther King proved overwhelming for his two foes.

After assaulting Sesshōmaru and putting Inuyasha in his place, the Panther King was undone when Sesshōmaru cleverly used Tenseiga to revive the three Panther Devas whom he had devoured to regain life. When their souls and lives returned to their bodies, the Panther King's power was drained. Inuyasha finished him off with a blow of the Kaze no Kizu and reclaimed the jewel shards from his neck. After he died again, the Panther Devas lost all interest in war and, in light of his betrayal, vengeance on their master's behalf. What happened to his remains after this is never specified, but it's likely that the Panther Devas left its disposal to the villagers.

Powers & Abilities

 * Immense Demonic Power: As the leader of the Panther tribe, the Panther King is a very powerful demon who was once a rival of and waged a war against Tōga himself though he was eventually defeated and slain. Upon being revived through absorbing the souls of three of the Deva Panthers and three Shikon Jewel shards, the Panther King is noted to be more powerful than even Ryukōtsusei (the Daiyōkai whom had dealt the wounds that ultimately killed Tōga) by Jaken. This is demonstrated in that in his revived form, he was able to fight against and overwhelmed both Inuyasha and Sesshōmaru at the same time. Only when Sesshōmaru used Tenseiga to revive the sacrificed Deva Panthers thus returning their absorbed souls back from the Panther King was he finally defeated by Inuyasha's Kaze no Kizu.
 * Immense Strength: The Panther King was enormous, and had strength proportionate to one his size, or greater. He was able to send both Inuyasha and Sesshōmaru flying back a considerable distance with relative ease that greatly damaged both of them.
 * Enhanced Speed: Despite his immense size, the Panther King has demonstrated himself to be quite fast as he was able to easily hit both Inuyasha and Sesshōmaru, whom being much smaller should have been more agile considering their already great speed.
 * Immense Durability: While empowered by three Shikon no Tama shards and three souls of the Deva Panthers, the Panther King is durable enough to emerge unscathed from almost all of the Inuyasha's and Sesshōmaru's attacks which included attacks made by the powerful Yōkai swords, Tessaiga and Tōkijin. Only when Sesshōmaru cut off his power by reviving the three sacrificed Deva Panthers was he weakened enough for Inuyasha to defeat with a single Kaze no Kizu.
 * Horns: The Panther King had one horn in the center of his forehead and other such protrusions over his body. He used these to stab and batter his foes to great effect. He was shown to knock Sesshōmaru back quite a distance and actually hurt him in the process.
 * Claws: The Panther King had large claws which he used to scratch and gouge his opponents. He could also launch these from his fingertips at great speed and force and generate new ones instantly, making them effective projectile weapons.
 * Electrokinesis: The Panther King could generate lightning and shoot it at his opponents. Whether this ability was one of his own or if it came from absorbing Shūran's essence is unknown.

Trivia

 * The Panther King was one of the few characters in the series to be killed by Tenseiga's life-powers. Others include Sō'unga, and Magatsuhi.
 * Despite being revived by his followers the Deva Panthers, he shows no real gratitude or honor, and ends up absorbing all except Tōran's life-forces (showing his ruthless nature).
 * Like the members of the Panther Devas the Panther King himself does show more catlike attributes about his physical presence than looking like an actual panther. Especially his yellow eyes do resemble the eyes of a cat.