Monsutāgakure

Monsutagekagure, or the Village of the Hidden Monsters, is a somewhat Hidden Village. It's location is unbeknownst to all, and it's happy that way. The village is far more primal in nature than other villages, for the strong rule the weak and so and so.

Location
The village is located within a hollowed out mountain that looks and feels hollow to intruders that are not welcome, thanks to their sealing masters. The mountain is nothing special, save for it being incredibly large. However it also is a volcano with an open hole on the roof. There is a second level held far within the sky, it is a massive island hovering high above the mountain. This second level is only accessible through a blood-sealed portal accessible only to those who are permitted.

History
The village actually became a village when the Shodai Onikage actually took over and stopped the wars plaguing the area between all of the borderline humans and the such. He brought a chain of command and as such boundaries. Now considering the Shodai happened to have merged with his sword, he is pseudo immortal. As of such, his reign lasted until he was defeated and sealed, as is the tradition for each Onikage to seal the one they defeat for the purpose of any Onikage who figures out the sealing methods can seal them within themselves. This little temptation is very unlikely, as they are all personally designed by the Uzumaki Branch sealing masters of the village.

Eventually, after about 150 years, there was a being capable of standing up to the Shodaime, he was also rather unique. Their clash is what hollowed out the mountain in the first place, or rather how it has a large hole on top instead of a peak. The Nidaime was of three clans of great prestige, each at their maximum capable of fighting with a Nanabi level fighter! Their battle lasted for around two weeks before the Nidaime was victorious, and the Shodaime was sealed, unconscious.

The Nidaimes reign was slightly more orderly than the Shodaime, but still was relatively carefree, no one cared if a Genin were to assault a civilian, they all had the right of revenge. This is a very often thing that happens, as it turns out that even the civilians tend to be very dangerous! The Nidaimes reign lasted for 116 years, before another challenger appeared.

This challenger, the soon to be Sandaime, was very similar to the Nidaime as his clans origins were extraordinarily similar. Their own fight lasted about 17 days, before the mountain not only became much more empty, but the Sandaime was victorious! And the Nidaime was sealed into the seal the Shodaime is in.

The Sandaime himself had a very prosperous reign, it lasted over 160 years! Over time many beings challenged each other so as to perform the sacred ritual. The ritual describes a meet every week where around fifty challengers fight against each other, and each winner is allowed to absorb the loser, normally gaining lots of power. The winner of each competition jumps vastly in reserves and normally gains all of the abilities of his absorbed. The catch is that you can only perform it once, however this doesn't stop some from just killing a winner and absorbing him.

Eventually the Yondaime-to-be showed up, and she challenged the Sandaime after some experiments from the gracious and very well funded scientist branch, possibly one of the most enjoyed and promising branches of their military! She successfully defeated the Sandaime in a mere 8 days! They were the one who destroyed the entire village AGAIN and made the mountain almost entirely hollow! Her reign was by Far the most carefree of them all, as she simply let the poor Cretans do their battles. Eventually she decided to introduce her own clan to her village, so she pulled one White and one Black Zetsu from her body, albeit with all the new abilities of hers passed on. These two started the clan of Zetsu's in Monsutā.

Even her great and prosperous reign came to an end, as her reign ended after a great 85 yrs, eventually someone stronger than her Appeared. The eventual-Godaime appeared and their battle ensued, however her techniques countered his greatly and as such the battle lasted 3 weeks! Eventually he overpowered her and used Bansho Ten'in to bring her to the sealer.

The Godaimes reign lasted for about 90 years before us successor appeared. Now the Rokudaime happens to have five bloodlines, three of which engrained him deeply with chakra in general as well as eternal youth and bone and shape manipulation and transformation. His battle with the Godaime lasted around seventeen days before the Godaime tired out, and was then sealed.

The Rokudaimes reign has lasted for forty five years and is still in progress, however this year is stated to be the year when all five previous Kages merge with the Rokudaime to create the eternal Kage. This has been stated to be the day that the six Kages of near equal power battle out and either make and underground extension of the village or just destroy the whole mountain!

Currently the Rokudaimes son is enjoying all of the bloodlines and abilities of the previous Kage due to the beginning of the ritual starting before he was born, however the chakra wasn't passed to him yet.