Final answer:
Mordred is told by the channel to channel his aggression against a god during the conflict in the story.
Step-by-step explanation:
Mordred is told by the channel to channel his aggression against a god during the conflict in the story. In the text, it mentions that Ethelred confronts a dragon and defeats it with his mace. This suggests that Mordred, being an aggressive character, is advised to direct his aggression towards defeating powerful opponents, such as a god, rather than causing harm to others.