Kingdom Of Wisdom: Wisdom Chronicles-book Four

Two years had passed since Wil created the portal between the worlds (Children of Wisdom); two years since the life-spark sisters Aimee and Desirée first met and reached out to each other following Wil's confrontation with Styxis in her throne room. With the melding of the sisters' spirits at the moment their life sparks were joined in a flash of magical energy, the demoness had been diminished.

Within the month that Wil, Caron and Roland departed Blackstone following the marriages of Aimee and Desirée to Lieutenant Crislin and Little Wil, the wizard Patrick's senses prickled at the presence of a third power inserting itself into his sexual coupling with Styxis. This cannot be allowed, he thought. This is a threat that must be destroyed.

Not long after Wil and Caron arrived back at Wisdom for Wil's long delayed reunion with Scrubby, the threat Patrick sensed had been eliminated.
But it was not destroyed as he had intended.