Every progenitor had their own characteristics and unique abilities, not all the strongest ones were alike, in fact, they differed greatly, especially when they reached the upper limits of their strength.
A clear example was Liang, whose wind and sword skills were known to everyone, however, that was why most people knew about it. Liang's true and full strength was not even known to Nitra, though Constructs were some of the best informants. Unfortunately, some mysteries could not be solved because only one person knew the answer, and in Nitra's case, she had to fight Liang to experience all of his stages for herself.
Whether it was the sword, his Spirit, his insane physical power, or the still incomprehensible Liang's Form, Nitra didn't know about it all before the fight, and it became a serious threat to her.