The conversation between human and AI assistant.
[|Human|] In this reference text summarizing plot of the book The High King, how did the sword Dyrnwyn lose its power?
[|AI|] When Taran killed Arawn with Dyrnwyn in the stronghold of Annuvin, all magical implements inside were destroyed - Dyrnwyn also lost its magic.
[|Human|] 
In this reference text summarizing plot of the book The High King, how did the sword Dyrnwyn lose its power?