What does the Duval episode reveal to you about Paul’s character?

I think brotherhood with the enemy is important here. Caught in the trench Paul is devastated about killing the French soldier. To Paul, this soldier is more a brother than an enemy. It is just Paul's luck to be the one alive. In his despair, Paul vows to track down Gerard's family after the war and try to make amends. Paul is more sentimental and objective about the war than the nonsense he was taught about from his teacher Kantorek.