"Those who focus more on the dark side tend to think always in terms of power. It must be more powerful. That's if they think of defensive protections at all. Before, while you were checking around, I started with a simple spell and built on it - hid my wand first, protective charms after that. Remember what I said about knowledge being power? Falls into that category."

He lifted his wand, which was the only warning he gave before he sent another spell at Draco - something more simple. Another disarming spell.