"Can you tell me why you killed all those people?"
Henry just wanted a reasonable answer. Even a single line he could hold on to. He needed something that would make him and all Humans feel safe, a fragment of logic amidst the madness of Adyr's actions.
Adyr knew this question would come.
This situation was almost identical to when he raided Cannibal's territory and killed dozens of people; at the time, the Player Headquarters dispatched an expert to assess his psychological state, observing every word and reaction to ensure he wasn't a mindless killer.
At that time he had explained the situation by claiming that the carnage was the result of necessity and survival in a desperate environment.
He had also made it clear he felt deep regret for all the deaths and that he understood his mistake and the importance of human life. In the end, psychiatrist Conrad had defined him not as harmless, but as beneficial. A dangerous tool pointed in the right direction.
