Although Elliot wanted to disbelieve what he was hearing, something in what he said made him think he might be right.
If he remembered as a child, his grandfather always got in between when his father started to get suspicious about his low talent. His father himself couldn't understand it, but his grandfather made a rule in the Clan while he was alive that said anyone who reminded Elliot about his low talent would be punished severely.
Everyone had to abide by it. Originally, Elliot thought it was a rule made to protect him from scorn.
Even Loen City knew about it, so no one openly made fun of him.
But...
What if it wasn't for that reason, but rather so that no one would touch the subject and thus manage to keep it hidden for as long as necessary?
Also, while it is true that he suspected that it was Jeff the traitor who sold his father and now he is fully convinced of that, he does remember that his father before disappearing had had an argument with his grandfather.
