If it were possible, the immediate shift in tone from the voice when Sephiroth intervened might have caused him to line-face even more. As it's pretty much his base neutral in such situations, however, only the tiniest fraction of his expression tightened further. He wondered if the reference to him -as it had to be him- as a Harbinger of the Calamity might be due to his chosen asterisk; or something else entirely more on a personal level...

Serge broke into those considerations, though, and Sephiroth looks over his partner once more before casting his gaze towards the path in the fog that's been created for them.

"Couldn't possibly be more foreboding..."