The demonic healer is the same demonic healer from 5.03 Siren Song
Marks the first appearance of Nick Lachey as Leslie St. Claire.
The return of Barbas, evil heads (avatars) and the demonic healer. They all appeared in season 5 though not in the same episodes.
The title is a reference to the bugle call to arms.
Shakti and Shiva's entry in the Book of Shadows reads, "Shakti, The Hindu Goddess of Creation and Shiva, the God of Destruction are commonly invoked at weddings because they're reconsidered to be the Ultimate Lovers. Shakti, also called The Ultimate Mother, and Shiva, together created All Things, and if they consummate their love again, All Things will be obliterated in the Universe will be reborn.".