"You could never hope to harm me." He's fully back to booming arrogance. And it is the pain that he likes. If you want some feelings out of him, and some of Vergil's that are new or at least not so common for you to come across...well he loves making someone suffer.

A shame it's so little in you. But he'll take it anyway, twist the root's speared end in. It's just exciting and comforting to him to show someone they're weaker than him and he could have them absolutely helpless. Assurance to himself that he's too powerful to be the one in that position anymore, as much as a desire to inflict the same pain he's had on others.

"I would need only a few cruel words to destroy you."