Gekko

Gekko (Moon Light in the Philippine-English Dub of TV5) is the estranged younger brother of Tsukikage served as a fifth antagonist in the Kaguya Arc of the Yaiba series.

Appearance
Unlike most of the rabbit people including his older brother Tsukikage, Gekko is a black anthropomorphic rabbit with ragged spikes and a single large curly fringe at the center of his head as his inner ears being light blue as a contrast to the rabbit's inner ears being pink and has two whiskers. He has a scar on his right eye where it was initially seen close until his right eye was restored when he obtains the Demon King Sword.

He wore two outfits as his initial outfit being a dark gold tunic with ripped sleeves a black turtleneck shirt with the collar being white, black pants and shoes. He also equipped with dark purple gloves.

When he invaded at the Mine residence, successfully captures Sayaka and throughout the Kaguya arc where she finally obtains her true primal form, his main outfit is a mix between the outfits of both Kaguya and Tsukikage; a black long military coat in a dark blue hue with a pale yellow turtleneck with a white collar, His cape is dark blue adorned with black and red pauldrons in gold linings and the interior is green, black military pants in a dark blue hue and matching military boots. He is also accessorize with red knee pad with gold linings on his right knee and the other being his elbow band with the same color on his left elbow.

Summary
He was at first a part of Kaguya’s invasion force on Earth a thousand years ago. However, he was defeated by the original Ryuujin and lost his right eye. During Kaguya’s 1000-year slumber on the Moon after her defeat at the hand of Ryuujin, Gekko created havoc on the Moon but was captured and imprisoned.

A thousand year later, Kaguya launched another invasion on Earth, facing Yaiba, who inherited Ryuujin’s powers. After discovering that she can return to her true primal form by sucking the extract of Sayaka Mine, Yaiba’s friend, Kaguya orders Tsukikage to release Gekko from imprisonment and ordered him to capture Sayaka, promising him the entire Japan. Before giving him the mission to capture Sayaka, Kaguya was amused to see both Tsukikage and Gekko are in fact brothers as he calls Tsukikage his Aniki (elder brother in Japanese).

Gekko raided the Mine residence to capture Sayaka, but despite proving superior to other Moon rabbits, Gekko was overwhelmed by Yaiba’s Ryuujin-ken. He then raided Area 666 in Kaguya’s base, taking the terrifying Demon King Sword. With this sword, Gekko proved too powerful for Yaiba and later even the combined powers of Yaiba and Onimaru. It took the duo a newly-developed technique, the Furaijinha, to defeat him. Gekko later fused with other Moon Rabbits into a being that in turn fused with True Form Kaguya into a being that in turn fused with Earth. Kaguya and all her henchmen, Gekko included, were eventually sealed into the planet’s core by Yaiba. In the anime during the fusion into Kaguya's true form, Gekko join hands with his older brother Tsukikage with the rest of the rabbit people until they were diffused when Kaguya was finally defeated by Yaiba's Ryuujin and was fall into her slumber for another thousand years. When Tsukikage was being informed by Kaguya who allows them to return back to the moon, Gekko informs his brother that she will be back home in the Moon which he calmly nods in agreement.

After the event of the Yamata no Orochi, Kaguya and all her underlings returned to the Moon, hoping to restore it back to a beautiful planet.

Weapons

 * Club: During his first raid on the Mine residence, Gekko used a club that resembles the tool used by Japanese to make mochi (a traditional food) on New Year event. This club has alternate modes such as bazooka or spear. Gekko can also use this to release blob monsters that resemble mochi. These monsters separate into independent beings if they are cut into pieces and are used mostly to immobilize the enemy by sticking themselves to him.
 * Demon King Sword (魔王剣 Maoken): A sword of terrifying power originally created by Kaguya to protect the Moon, but its power proved too much, resulting in the current un-inhabitable state of the Moon and thus the sword was secured in Area 666 of Kaguya’s base. After his first attack on the Mine residence failed, Gekko intruded Area 666 and took the sword, and with it he easily overpowered Yaiba with the Ryuujin-ken. This blade can turn the evil spirit of the user into energy attacks.