A Mid tier king-level magic beast, Rupture!
Who the hell is Rakuzen to write such a beast off so easily? Has he forgotten that he is only using Lucien's body and as long as Lucien is concerned his body is not ready to take on a king-tier magic beast, regardless of its bloodline, whether weak, strong, or just mild. Lucien knew his current body capabilities and something told him that even if he were to go overboard by combining the strengths of all three magic beasts he still won't be able to face this magic beast.
In his opinion, the strength between the mortal realm and the spirit realm is so wide and vast and that applies to magic beasts as well! At the king level, the magic beast has far surpassed the realm of mortals and has taken a bold step into the realm of the god beasts. Its comprehension of the laws of nature has deepened and its control over the elements has strengthened greatly. It has practically become one with the element!