That youthful power was proof that humans are no more than beasts. Should one let their spirit rage freely within, it will certainly lead to their collapse.
By practicing self-restraint, one truly becomes human. At the same time, this is how contradiction is born. Just by being human, there are tribulations one cannot overcome.
To forget about being human is to become a beast of one's own volition. One could be overtaken by that rage, or use it as sustenance. The path he chose would decide the outcome. One can only be judged by the life one leads.