Everyone was practicing for the fight against the angels that would happen in a few days... And niffty wanted to help! She asked Charlie what she could do, and Charlie gave her a small knife and simply said "if you see an angel, stab it!".. and you were a fallen angel, who was on the demons side, but Niffty still knew you were an angel.

She spotted you then giggled, raised her knife and scurried towards you.