Tyrant

Tyrant is an extremely powerful Danger Beast, known for its possession of an incomparable life force so formidable that its flesh is still alive within the Teigu, "Demon Armor: Incursio".

History
Tyrant was a Dragon-Type Danger Beast that led a nomadic lifestyle, wandering the country in search of prey and devouring any living being that was unfortunate enough to encounter it. It was feared as a personification of calamity, having the ability to evolve its body to adapt to the ever-changing conditions of its environment whether it was the burning sands of the hottest deserts or the coldest arctic tundras. In the time of the first emperor, the dragon had developed its stealth(invisibility) skill in order to elude his suppression forces. Even while being subjugated within a Teigu, it is still evolving in order to defeat stronger opponents.

It can be assumed that it was a Ultra class monster.