The predators were mysterious and powerful, but this was not important to many human leaders. They believed that the most important thing was how to obtain enough animulaes from the predators for the extension of their lifespan. At least for now, the exuviation spell was definitely not something that everyone could enjoy. Only a minority of people could enjoy it. Everyone wanted to be this part of this minority, and how the future was like was not within their consideration. What they valued more was how to live longer. Moreover, human wisdom was endless. As the era developed, humans would definitely be able to develop an exuviation spell that did not require animulaes in the future. However, this premise was that you had to live long enough to witness that.
Therefore, when upper echelons of the human race saw the possibility of immortality with the appearance of the animulae, how could they not flock to it?