Although Elwin wanted to watch the battle, he knew it was just a passing thought.
This kind of fight was simply not something he could get involved in.
To begin with, right before entering the castle, Elwin had seen the glass orb on the staff of one of the figures in black robes flash briefly, after which a magical shield materialized right in front of him. All of Snape's spells crashed against it and were instantly neutralized.
Chapter 83