Courtesy of Wikipedia
Introduction
Onmyō Taisenki literally means “The Chronicles of the Great Yin-Yang War.” The series makes clear references to I Ching and to the Taoist theory of the five elements: Wood (木 ki), Metal (金 kin), Earth (土 chi), Fire (火 hi) and Water (水 mizu). Various Taoist elements are incorporated within the story: the existence of the four Kimon (鬼門, lit. “Demoniac Portals”), the use of cards that act as the Onmyōdō's amulets (闘神符 tōjinfu), the use of trigrams to represent direction when the Drive is swung (North-South-East-West is represented as 坎-離-震-兌 instead of 北-南-東-西, respectively), the emphasis on the balance of the sekki (the 24 seasons), and the character Nazuna, who is a Taoist maiden. Also, the show itself can be split into four seasons (13 episodes each), each with its distinct story, purpose, and goals.
Riku Tachibana (太刀花リク Tachibana Riku) is a 12-year-old Japanese boy who lives near Tokyo. Never having met his parents, he lives an ordinary life with his adoptive grandfather. His grandfather had taught him a series of strange hand movements, which Riku did not know the purpose of until the day his grandfather is attacked near his shrine. But it is not an ordinary attacker. The attacker is a Shikigami (式神, lit. “Ritual God”), a strange monster with a human owner. Riku comes to the scene and that's where he first gets in contact with his Drive (神操機), the device he uses to call and make a “contract” (契約 keiyaku) with Kogenta of the Byakko (白虎のコゲンタ), his Shikigami and, from that day on, best friend. The Shikigami needs, for special attacks, a special series of Seal (印, In), one of which happens to be the strange hand movements Riku's grandfather always taught him. As Riku's grandfather decides to leave the house for a journey, the 10-year-old boy Souma Asuka (飛鳥 ソーマ Asuka Sōma) and the 10-year-old girl Nazuna (ナズナ) rent rooms in Riku's house. The 17-year-old man, Masaomi, who teaches Riku the secrets of Onmyōdō (such as the use of Tōjinfu, for example), drops by eventually. The three of them have “contracts” with Shikigami. The main events of the Onmyō Taisenki anime are related to the menace of the Chi-ryū (地流), a powerful Japanese financial group related to the Onmyoudou; attempting to open the four Taiten (Yondaiten [四大天, lit. the “Four Great Heavens”); and freeing Utsuho (ウツホ), a boy who was born with the power to control yōkai (妖怪), and had been imprisoned for thousands of years.
Onmyō Taisenki shows monsters called Shikigami. There are 24 families of Shikigami (three per family, for a total of 72) to represent each Solar term. These monsters are extremely powerful, and their special abilities (必殺術 hissatsu waza, lit. “certain-kill techniques”) are activated when their owners use certain sequences of In. Every Shikigami has its own In sequences and some have special weapons, which are also activated by the In. Every Shikigami has its own name and a class/family. For example, the name Byakko no Kogenta means Kogenta of the Byakko (白虎 White Tiger), one of the four great Japanese Gods; the other three are Seiryū (青龍 Azure Dragon), Genbu (玄武 Black Tortoise), and Suzaku (朱雀 Vermilion Bird) family. Class names are usually named after gods and flowers.
The Shikigami can transform into a Daikōjin (大降神 Giant Descended God), which is a giant and extremely powerful form where they usually go berserk. Although Nazuna says that a true Daikōjin occurs when Mind-Technique-Body are together, Riku has been able to summon one when he is highly desperate and emotional (usually when Kogenta is about to be killed). Shikigami can also transform into Daikōjin form by forcing a Tōjin stone into a Shikigami, as Isou does to his Shikigami, Fuji, in Episode 20 (or by inserting a special chip made from the Tōjin stones into the drive). However, these methods only produce a confused and pained Daikōjin and causes the Drive to sprout coils that will eventually kill the Tōjinshi if the Daikōjin is not defeated. In addition, members of the obliterated sect Jin-ryū have been able to change their Shikigami into Daikōjin by using lengthy series of In.
Later in the series when Kogenta and Rangetsu were fighting together against Mikazuchi, both Riku and Yuuma gain the Master Drive and their partner Shikigami are able to transform into a Chōkōjin (超降神 Super Descended God), where the Shikigami still have their sanity but a different appearance. Later, Kibachiyo and his partner gain the Master Drive and could also transform into a Chōkōjin.
When a Drive is activated for the first time, the Shikigami will appear behind a shōji and asks what the owner desires, and if it is to the Shikigami's liking, it will accept and a contract will be formed. Once the terms of the contract have been fulfilled, the Tōjinshi and Shikigami will part. However, when a contract is broken (Shikigami dies or Tōjinshi tries to break the contract), the Tōjinshi loses all the memories built since when he first contracted with the Shikigami and usually wanders around lost and depressed while the Shikigami is sent to Naraku (奈落 Underworld). Similar events happen with Riku in Episode 23-24, as he rejects his contract with Kogenta and consequently does not remember people he only met after he formed the contract, but still remembers his childhood friend Momo.
Onmyou Taisenki Toujinki Battle Digivice
This is the toy based on the digital device used in the anime Onmyou Taisenki, which requires the same kinds of movements as in the show to aid Shikigami in battle.
Extra Notes: Although this Onmyou Taisenki Toujinki Battle Digivice is used, it still looks brand-new, save for the box being a bit worn, and it comes with both a pre-installed battery and the instruction manual (though in Japanese). Since this device came directly from Japan and is in Japanese, it will take some guesswork to figure it out, along with searching for some hints in the instructions via the pictures provided. However, it seems a bit interesting once you figure it out. Moreover, this device is out-of-print, as it was released over a decade ago, so it's a bit rare (I can hardly find any online). Also, keep in mind that I am willing to take a look at any offers, so you're welcome to send me a message, just in case. However, please keep in mind that eBay takes 10% of whatever this item sells for plus the shipping, and Paypal takes its profit as well (so, I would actually be getting a bit less than what the item sells for). In addition, I will throw in a free unopened Japanese Tamagotchi and anime-related gift. Furthermore, upon shipping the items, I will supply you with a tracking number, if it is available for the type of shipping chosen (if it is not, then the most I can do is get a confirmation number). Lastly, if you order other things from me at the same time, I will combine shipping. As a side-note, shipping and handling includes the cost of shipping the item plus the Tamagotchi and anime-related gift, as well as the cost for the box, packing material, etc.