Is my blood a melting pot of bloodlines?
'What have I done?'
It was the only thought going through Katharina's mind—what had she really done by turning Vergil into a Demon?
Initially, she thought she had just shared the girls' blood for nutrients and energy, after all, demonic blood is bathed in demonic energy, or rather, it is demonic energy itself, as the heart pumps blood while generating demonic energy.
However, it didn't just transform into energy, it completely became Vergil's Blood, which had absorbed its characteristics and enhanced itself.
She had already sensed that Vergil had a strong lineage, strong enough to deny her access to the contract they had made, the Master-Servant contract.