The Senninkai (realm of the Dieties) are made up of 2 main floating islands, and a host of other floating islands. The 2 main islands are: Konron Mountain and Kingoto Island. The other, smaller Senninkai related locations include: Jyoka's Horai Island, Taijuroukun's Togenkyo, and Chou Kou Mei's Queen Joker Version 2.
The first of the major Senninkai islands is Konron: home to Taikoubou and the human Shendou.
Set up a very long time ago by Geishitenson-sama. Kunrun specialise in human Sennins, so there are very few youkai-sennins around in Kunrun, except for Youzen, Hakatsuru and a few other minor characters. Underneath Geishitenson-san, is the rank of Ryukitsu (and Nentou) with the 12 Sennins following (equal in rank with Taikoubou) and then the rest of the deciples. Kunrun mountain itself is a weird verticle shaped piece of rock with lots of tiny rocks floating beside it. However, do not underestimate it, the technology held inside are quite impressive. It even has a Geishi-Cannon. It is said that Kunrun only has around 400 over diciples.
Kangen Mountain - Taiitsu's Home
This Squarish island located near Konron Mountain is called Kangen Mountain - it is the home of Taiitsu Shinjin, and also where he spends most of his time inventing new Paopeis. This is also the place Nataku regularly visits and destroys whenever he wants Taiitsu to 'fix him', or enhance his battle capabilities.
The Second major Senninkai is Kingoto Island
Set up by Tsoutenkyoushu-sama and it mainly specialise in Youkai-sennins (as in animal or creatures other than humans training to become Sennins) with some exceptions (e.g. Sengyoku, Bunchuu, Ryokan, Ryogaku and ofcourse Ou Tenkun). Underneath Tsoutenkyoushu (in the old days) were 3 generals and they were Chou Kou Mei, Dakki and Bunchuu; after Chou Kou Mei and Dakki left the Sennin Kai to set up their own fort, Bunchuu was left the only one in the 2nd rank, under him lies the Juttenkuns, and under them are the minor monsters. This round, pyramid-like Sennin Kai is bigger and definately more powerful than Kunrun, however it is due to the weak psychy of the Youkai Sennins (other than Outenkun) that resulted in their massive lost during the Sennin War. It was predicted that Kingoto, the mountain itself is 5 times that of Kunrun and hold over a thousand youkai sennins. The radius of Kingoto's base is around 15 kms long. The most powerful paopei held in Kingoto is the Tsouten-Cannon!
Kingoto Island is far more complex in structure than Konron Mountain. As it is home to about 1000 Youkai Sennin, each with different needs and specialities, Kingoto has basically created special "realms" or "realities" within its own confines. Those sphere like structures is a powerful, spatial paopei called "Akukans", which are used by the 10 Juttenkun members as their homes and their weapon of choice.
Just like Konron Mountain, Kingoto also has an 'internal sphere' which resides as the control panel for the entire island nation. Powerful Sennins like Bunchuu (and it is assumed that both Dakki and Chou Kou Mei could as well) could move the island literally thousands of miles. Not only that, Bunchuu also activated the use of the "Tsouten Cannon" against Konron Mountain during the Sennin Wars, as well as a creating a magical sheild around the entire island strong enough to stop the "Geishi Cannon." Overall, impressive technology.
Hourai Island is arguably the 3rd Sennin Kai, belonging to Jyoka and Dakki. This love or heart shaped island is actually only the doorway towards the real thing behind it. When Taikoubou first encountered it, he was warned by Taiitsu that this is not the real thing, later, Sinkyohyo destroyed the outer facade with his Raikoupon, revealing a Warp Zone on the other side.
Once they entered the War Zone, they came upon a new world in space (outside of Earth's hemisphere). This is the real Hourai Island, a huge paopei probably the size of the moon, with highly advanced technology far superior than both Kingoto and Kunrun combined. I can assume this becasue even after the battle with Jyoka, it still stands straight with minimal damage.
Hourai Island has its own vegetation and unique flora and fauna. The island was first created by Jyoka to house her real body, and later used by Dakki. In the end, Hourai Island became the new (and only) Sennin Kai.
Togenkyo is Roushi's secret haven. You could almost say that Roushi was the one which developed this place. Although it isn't technically considered a Senninkai, as other than Roushi himself, all the other inhabitants of Togenkyo aren't Sennin, just regular or irregular humans.
Tougenkyou is actually a big peice of land that is stuck on top of a massive mountain, but it is always surrounded by clouds so that no one knew it actually existed, leaving it secluded from the outside world, just the way Roushi liked it. Roushi said that Tougenkyou is a place where everyone is equal, and the town itself is fair and just in its proceedings, because there is no war, no fights, no one selfish enough to want to gain advantage over others, every thing within Tougenkyou is in the right balance of harmony.
Togenkyo is basically Roushi's idea of Shangrila, or a Garden of Eden. A perfect place of peace and harmony.
The Queen Joker Version 2 (No, I do not know what Version 1 looks like) is Chou Kou Mei's home. It is an subsidery island of Kingoto, but Chou Kou Mei seemed to have moved it away from it's mother island and had it rested here (on a giant lake) for aesthetic purposes. Like all other islands, the Queen Joker Version 2 is basically a giant paopei that can move and be used as a weapon. Although Chou Kou Mei mainly used it as a stage of his gallant battles with Taikoubou and company.
The Queen Joker Version 2 have 5 different floors. In the manga, Chou Kou Mei used each of these floors as the battle grounds between Taikoubou's company and his own minions. Each of these levels have their own 'boss', which Taikoubou and company had to defeat first before they can continue on their journey to the top. Chou Kou Mei himself, resides in the top level. Below are a list of images which details what the Queen Joker Version 2 looks like internally.
External view of the Houshindai
Originally, the Houshindai is described as a mechanism that stores all the souls of the Sennins that were killed by Taikoubou and company. There exists an universal law against the killing of Doushi and Sennins, as such the Houshindai provides a way of escaping that law, since all the souls that were imprisoned into the Houshindai didn't actually die, their souls have just been captured and stored away, that's all.
As the story progressed however, the Houshindai's role began to change. It still acts as a devise to house souls. However, it is reason or 'purpose' behind holding the souls that have evolved. Instead of just keeping the souls of evil Sennin at bay, it is instead used as a conduit in which all the soul's combined power (even after death, the Seenins still have energy) can be used by the Fuuki in his fight against the ultimate foe, Jyoka herself.
Internal view of the Houshindai
The inside of the Houshindai isn't meant to be cages in which souls are stored. Instead it reflects the existing Senninkai islands. This means that each soul will have their own home located on one of the smaller islands floating inside the Houshindai. Quiet comfortable really.
Later, the Houshindai evolved again and rebuilt into a new "Shinkai" or realm of the Gods. This just means that it inhabits more space, and holds more souls than before.
The Houshindai, later changed to Shinkai, is eventually moved inside the Warpzone area originally found by Taikoubou when they passed through in their search of Dakki and Jyoka. This means that the Houshindai / Shinkai became part of the portal which leads from the Human world (Ningenkai) to the new Senninkai (Hourai Island). As such, the Houshindai was appropriately renamed as Shinkai (realm of the gods), which will have the ability to watch over the human world and help them along if necessary.
The Country of In is made up of its capital city in the centre (Chouka - where Chuuou lives), and 4 major provinces surrounding the city. These provinces are simply known as the "Northern Province", "Eastern Province", "Southern Province" or Western Province". Each of these bordering provinces have their own governing lords - often referred to as 'Kings', but they too report directly to the central monarchy - Chuuoh as he is the only true emperor.
The Country of In
Chouka is the capital city of the In dynasty. It is located right in the centre of the country, and is where Dakki, Chuuoh, Bunchuu and the rest of the ruling class live. Kou Hiko (the Bu Seioh - which basically translate to Chief of the Millitary) use to live here as well until both his sister (Kou Shi -one of the concubines to the emperor) and his wife committed suicide, that's when he basically packed up his entire family and left the capital to travel to Seiki (Western Nation).
Kinjou is the actual royal palace in which Dakki and Chuuoh lives. It sort of translate to the 'Forbidden Palace' or something like that. The palace is huge spatially, able to house up to hundreds of thousands of people just in the courtyard.
Chinto Pass is the home of Lisei, his wife Inshi and is the birthplace of Nataku. This is also the area when Nataku first 'died', and when he later revives and comes to confront his father and Taikoubou. Not only is Chinto Pass of sentimental value to Nataku and his family, it is also an actual blockaid area between Chouka and the northen countries. Lisei as the head of the pass is responsible for making sure traders and civilians are able to cross the pass without problem, but stop any invaders and other people reaching Chouka. However, since Lisei is a supporter of Taikoubou, the pass pretty much became useless in the defence of Chouka.
The royal graveyard was erected some hundreds of years ago to house all the dead from the In Royal Family. Bunchuu old friend - Shushi, is burried here also. It was due to a promise made to Shushi which led to Bunchuu being so obsessed with reviving the In Dynaster no matter what the circumstances. When Bunchuu died, his soul actually traversed across the country, from his place of death to Chouka (in order to say goodbye to Chuuoh) and to this graveyard (to apologise to Shushi) before flying to the Houshindai, where his soul belongs. It is expected that when Chuuoh dies, his corpse will also be transported here for burrial. I don't know whether or not the new Zhou rulership will be useing this same graveyard or errect something of their own.
Each of the bordering nations surounding Chouka (ie. the Northing province, the Eastern province, the Southern Province and the Western Province) all have their own capital cities. The capital city of the Northern Province is Suujou - the home of Suukokuko and his Reijyu - Shinyou.
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