That kind of conclusion is not far-fetched, because Aldrian himself is a living example of a reincarnated being who slowly regains the memories of his past lives. If the devil lord is actually a reincarnated being who still retains the memories of his past lives, then he has to admit that such an opponent indeed dangerous.
In terms of strength, they may not be so far apart, as the formation covering the continent limits the devil lord to, at most, the peak of the emperor stage—though he can still exude power beyond that. Aldrian, with the combination of all his domains, can also release power beyond the emperor stage, as seen in his battle with Cardinal Carsius.
