Yuamu's team has been trying to uncover how the carding system works. Dinois suspects that Phaser is hiding some secret about the Relic, so she confronts Tremolo about it. The fact that someone is suspecting his brother doesn't sit well with him. On top of that, he's also having suspicions about Zuwijo, Dinois's commander. And so, he challenges Dinois to a Duel.
