History

The exact age of the fortress has never been mentioned, however it is said that the fortress came to be thousands of years ago. In the Initiation Ceremony Yan Lin speaks of the "twentieth wind of the fourth era of Kandrakar".

The history of Kandrakar is almost as ancient as time itself and connected to many legends and tales. The five nymphs, the elemental queens, the Veil and many speculations that arise when we take a look at the walls of the fortress that show events of the past.
In the following I will try to reconstruct the history of the Kingdom Kandrakar as best as I can without crossing too many other fields. If necessary I will link to other studies here in the main studies or in my Memory Lane in order to explain certain aspects of history more thoroughly.

"When the world was still young, all spirits and creatures lived under the same sky. The universe was one huge kingdom, ruled by nature for thousands of years. Then spirits and creatures  got to know evil, and the unitary world split between those who wanted peace and those who wanted to live on others' suffering. "- Yan Lin, Issue 1

In the special The Core of Kandrakar this part of history is described a little differently. There "nature" is equalized with the five nymphs, absolute beings that were there since the beginning of time. It is described that: "A negative energy... brought hatred and violence by breaking the harmony of the originals..."  It's never said what exactly is meant by "breaking the harmony of the originals". It is possible that the nymphs themselves got to know evil or their bond was broken by said energy which then exploded and invaded their world. It can't have been a fight between nymphs since the special also sais that all five created the Fortress of Kandrakar together. 

Kandrakar was created  to combat this negative energy.
N'ghala, nymph of the stars, became the first oracle (other Oracles here) and ruler of the kingdom Kandrakar. The nymphs had supervised the many worlds from afar, not interfering with them directly and so N'ghala continued from the center of infinity.

"Inside, the wise and scientists gathered, the best of each world... powerful and higher entities called to take care of the worlds." as the special The Core of Kandrakar tells us.

To keep evil from spreading further throughout the worlds, the wisemen of Kandrakar evicted the dark energy "to the frontiers of the universe, to the dark place called Metaworld." (Issue 1) and sealed it through the Veil, a magical barrier surrounding Metamoor (or Metaworld, or Meridian).

In issue 9 Yan Lin sais the wisemen already knew of the Light of Meridian while creating the barrier and that it was a temporary solution to suspend evil until the arrival of the Light. She was supposed to "reestablish balance". But Elyon would not be born for (possibly) hundreds, maybe thousands of years and darkness leaked through the barrier over and over again.
And so the guardians were introduced in order to contain evil, protect the fortress and bring its justice "everywhere there was need for it" (Special: The Core of Kandrakar)

Later Phobos states that the veil was created specifically for him, to keep him trapped. However that would mean that he too had lived a hundred years before Elyon was even born, which isn't impossible but still seems unrealistic. Especially since Weira disappeared after giving birth to Elyon and why would she let Phobos reign in terror if she, the true queen is still around?

The first known threat besides Metamoor is Meter, the queen of spring. It is not clear if the elemental queens where before the nymphs, or after. In issue 79 Yan Lin speaks of "the old stories about the kingdom" which could both refer to the kingdom of Kandrakar, or the ancient one kingdom the universe once was before darkness fell. Himerish says "The stories older than time itself" but the nymphs have only been there since the beginning of time if we read back in The Core of Kandrakar.

Either way, she was the elemental queen of earth and was destined to fall to her arrogance (maybe through the negative energy?) and become a monster. She build an army and attacked Kandrakar but the other elemental queens "resisted". This probably means they protected the kingdom which makes me wonder where the guardians where back then. The fortress already existed so either this was in the short time before the guardians were introduced or it was during the first generations of guardians who were too few to handle the Heart of Kandrakar properly which might have left them too weak to defeat Meter. Or maybe the Kingdom already existed but not the Fortress with the Oracle and Wisemen?

In the end Meter was defeated by the other queens and banished into a place far from any earth.

This is a picture from a wall in the underworld of Kandrakar. It shows pictures, stories, memories of ancient times.
We see a wise man or maybe even oracle fighting monsters. Unlike the other walls of Kandrakar, this one is explicitly shown as a piece of history of the fortress.

It is also known that the Sealing Ritual has been practised "ages ago" at least once before it is performed again in issue 75. It is not said when exactly or for what purpose.