The Ongots Taslagch

The Plane Breaker

From the depths of time arose a mage so powerful that the cosmos itself bent to her will. But death comes for all creatures, even those that can bring the endless planes together.

The Plane Breaker is an ancient book of mythical power, whose true origins are not, and may never be, known.
The Archmage Arilia was one of the most powerful mages in the history of the planes and was known as The Planeswalker for her vast travels and her ability to cross unhindered through all planes of existence. Legend has it that she had used her magic to stop ageing, living many thousands of lifetimes of ordinary men yet one day she gazed into the future and saw an endless darkness looming, and then she looked into the past and saw a cloaked figure following her. She interpreted this as an omen of her impending death, something that she simply could not accept. She had spent thousands of years walking across the planes and she knew that the knowledge of how to stave off death, the knowledge she sought and desperately needed was not to be found in them.
Legend has it that she used all her wits and magical ability to seek knowledge from outside the planes themselves, from outside the boundaries of our universe, beyond that which we can fathom. Nobody knows what she found on her journey but when she returned to the Planes and saw that death was still following her she faced him with laughter. This is how her disciples found her; with a smile frozen upon her face in an empty stone chamber.
The archmage had only one possession with her when she died. An unassuming black book adorned with undecipherable symbols that seems to drink the light that falls upon them. Her apprentices, realizing that this book did not originate in this plane of existence, or even in this universe realized what power could be hidden in it. At first the three eldest disciples, second only to the Archmage in power, attempted to harness the books power, but one by one they succumbed to madness from trying to decipher the text. They formed the Triumvirate of the Magium and they used the Ongots Taslagch wreak havoc across the planes, in a series of conficts known as The Plane Breaker Wars

In the end, however, they could never unlock full power of the Ongots and the book turned upon it's owners, feeding upon their magic until nothing remained but empty husks.
The remaining apprentices who had worked against the Triumvirate decided that the book was far too powerful to be allowed to remain in existance but whatever magic they threw upon it the book was unharmed. They then made a plan to split the book and bind it into their very souls and hide it in the remotest regions of the cosmos never to be spoken of again.
Yet , the legend survives... And so does the Taslagch