Signum frowned disapprovingly. Shooting people in the back was generally good tactics, but that didn't mean she had to like it. That was how Aria Lotte had cut her down... pretending to be her ally, exploiting her connection to the Book, and attacking from concealment. What Momo had said about damaging her own body was bad, too- she'd realized that the girl was suffering some internal damage from using her magic, but either the damage was accumulating or the girl was pushing further and further beyond her limits. She needed to cut back or she'd destroy her own effectiveness, but how could you tell someone not to give their all in the situation they were in?

Signum did in fact know the drug, courtesy of Hayate's frequent stays in the hospital until the Reinforce's magic had allowed her full recovery from the damage the Book had inflicted. "It's a painkiller. A strong one, I believe."