She's a "super magician" yet she can't put out a fire on her own store? Yeah that makes sense
Most humans in this world only have 2 elements. Some rare people have 3 or 4 elements. Lily's Master has 7 elements. Is it that odd one of her elements is not water? She has Light which from the hints her master does not have. She may have 5 elements Light, Attribute, Fire, Wind, and Earth. Possibly does not have Debuff, Water, Dark, or Holy magic.