Nothing bad, in that he's always been textbook Lawful Good in the extreme. But explain that he was murdered during a battle? No. Not a burden he wants to put on her.

He tilts his head at her, a little quizzically. "Certainly Bianca and McCoy--he's not as frightening as he might seem," Septimus interrupts himself, because McCoy can seem a little much, he suspects. "But I trust your judgment as well. If you're worried, ask me--but this is your life and choice. I think you're more than able to do this." He gives her a faint smile.