Nassus was surprised when the blade on the side of Kane's armor managed to inflict a wound on his body. He knew that the armor was made of dragon scales but didn't know that the blade also came from a dragon.
'Your father's memento is worth more than I originally assumed.'
He was surprised shortly after when he tried to block a large swing Kane tried to make, putting his whole body weight into it. It was strong enough to make him lose his balance, and when Kane followed it up with an even faster slash, he was forced to retreat a bit, but then something even crazier happened: Kane managed to get even faster and landed a shoulder tackle.
Nassus tried to use his control over his domain to shrink the space between him and Kane, but this time he paid more attention than before and noticed a foreign power messing with his domain, which quickly undid the changes he made. An ability that wasn't part of the cast of dragons that accompanied him.