((Flee!?! The Great Septimus does not flee! He does the opposite of 'flee'. Or... maybe he will... all depends on what you have planned for the sequel. Like, does it take place immediately after the events of this one or is there going to be a time skip? If it's the former, then I could see him fleeing, but if it's a time skip deal, I'll have him die... actually, I've been planning on having him die, but he certainly won't be 'resting-in-peace'!))
Septimus watched Yure cough, laughing lowly to himself. He did stop laughing once the girl became sick, however, grimacing at the sight. "Ugh! That's... that's pretty gross." It took him a moment to realize something very familiar about the sight before him. "Wait... didn't that first demon girl say that you...!! No! That's impossible!" Septimus couldn't deny it; Yure was using a more focused form of the spell he had previously used to kill her sister! The fool! Even Septimus couldn't control a more powerful version of 'PWD'! They'd both be killed if he didn't try to stop it.
Septimus flew higher into the air, staying just out of the liquid's reach. He quickly erected several barriers between him and the spell, though these would only hold the liquid back for so long. A sealing spell would work, but those were largely White magick, something Septimus had lost touch with long ago. Yet, it was his only option; he had to reconnect with his White magick roots... and soon.