Su Yu did have a slight understanding of Sylvanas.
Sylvanas was very similar to Xi Fan.
Xi Fan had once sacrificed the lives of the people of Forest City to obtain the [Frenzy Fragment] to increase his strength;
The way Sylvanas enhanced her abilities was by devouring and torturing souls, utilizing the power of deceased human souls to undergo a complete transformation of her strength.
Two hundred years ago, Lai Yin was just a duchy with a population of just a few hundred thousand. Sylvanas followed the emperor of Lai Yin on his conquests, eradicating all nations on their continent and expanding their country into a huge empire with a population of a hundred million.
In the wars, Sylvanas also devoured enough souls to allow her to ascend to legendary status.
