Duke Org Rouki

Duke Org Rouki appeared in 2001 TV series called Hyakujuu Sentai Gaoranger. Duke Org Rouki (デュークオルグ 狼鬼 Dyūku Orugu Rōki, Wolf Demon) is a wolf-like Org born from the mass of evil energy contained inside the Dark Mask, the Thousand-Year Evil (千年邪鬼 Sennen Jaki), called himself the most powerful warrior of the Orgs.

Long ago, Shirogane used the mask to evoke his three Power Animals' combination at the cost of becoming Rouki himself. Vainly attempting to control himself, Shirogane had his allies seal him away into a stone coffin.

But once released by Highness Duke Org Ura, Rouki is bent on exacting his 1,000 year grudge on the Gaorangers with no memory of his human life. In the process, while the taking Gao Jewels of GaoElephant, GaoGiraffe, and GaoBear & GaoPolar, Rouki begins to recover his memory as Shirogane. When the time of the full moon came, when his power is at its zenith, Ura implants a special grasshopper to modify Rouki's memory and willingly give the GaoJewels to the Highness Duke. By then, the Gaorangers learned the truth and Shirogane was finally freed from the evil energy when the Gaorangers used GaoKing Striker to force GaoHunter apart and break the curse.

However, Rouki was then released from his imprisonment and he attempted to kill Shirogane for using him and his power. Rouki was eventually defeated when GaoSilver joined forces with the other Gaorangers and Rouki was finally killed by GaoHunter Justice with the Dark Wolf Mask destroyed. But the Thousand-Year Evil Rouki was made of escaped and scattered, with Ura cultivating it in various Orgs. Each time an Org is killed, the evil energy become even stronger. When GaoDeers sealed the energy, Ura had the Dukes capture Shirogane, who forced him to reabsorb the stronger evil energy, and become Rouki again but he was able to reject the power, unaware that it was all part of Ura's plan. But thanks to GaoIcarus, the Thousand-Year Evil was finally destroyed for good.

Arsenals
Rouki wields the Crescent Moon Blade (三日月剣 Mikazukiken) which can perform the Crescent Wave (クレセントウェーブ Kuresento Wēbu) and Moonlight Sonic (ムーンライトソニック Mūnraito Sonikku) attacks, and like Duchess Org Tsuetsue, he has his own Wolf Seeds (ウルフシード Urufu Shīdo) that can enlarge Orgs by the command "Wolf Seeds, allow the fallen to regain their enormous wicked power!".