Who's the Traitor?

Who's the Traitor? is a Versal quest started by Zero.

Part of The Versal storyline and A Plea from Versal: see every quest in order.

Requirements

Offer: I won't turn around. I'm watching her....Rachael told you Will has a spy here. I believe it, and I hate that I do. Larelle's cave, Wu Gong's house, Arsen's plant. Will's people were right behind you every time. That isn't luck.
Every Shadow Knight carries a seal, a little spider. The spy has one hidden somewhere. If Will finds out where this girl sleeps, it's over. Sit with me. Tell me everyone who has touched the Relic or seen Will's map. Will you help me?
In progress: Sit down and talk it through with me, Zero, here at the Versal Nexus. Who has touched the Relic or seen Will's map?
Completion: (Not Pietta, not Elpam. Then you remember the brass pendulum Cassius swings over every map you bring him. There's a tiny spider engraved on its weight.)
Cassius. Lukan's own student. He sold every step you took, and he knew where the girl sleeps. His chair is empty. He ran before anyone could ask him why.
Tell his brother. Benedict is here at the Versal Nexus. Without a pendulum, Lapis and Lazuli can't steady the Relic enough to find the last two Teardrops. Benedict will know where Cassius ran. Nobody takes the girl. Not while I stand.