The pair had listened to the whole tale with interest and barely disguised skepticism respectively. One of them's grin at the start slowly delved into a frown as the story went on and he realized where this story was going while the other's frown eventually grew into a wide grin as she had been right, all along. He knew now what she had known this whole time. Her and him, that's all that was needed. Everyone else were liars, crazy, useless or unnecessary. Yuki only needed Yuno and Yuno only need Yuki.
"...No. No no no, that can't be. We...he, he was just a little kid playing music. To steal and assault..." He frowned, bowing his head as Yuno stepped up in front of him, as cute and giddy as ever.
"You see, Yuki? You trusted that little mischievous boy, saved him from me along with that big guy...when all along he was a little thief and violent guy with a mask far beyond him. I should have sliced his head clean off. I would have. Don't you see? All for you! You and me, that's all we need. No one else."
His fists were clenched so hard to the point they drew blood as he digested this fact.
"He lied to me." He closed his eyes. Yuno, for all her off-putting psychotic moments...she had never lied to him. Not once since they met and all the way up to the midst of the games back home, when they'd been dragged here by whatever or whoever. She was honest.
"You're right." He admitted, reaching out to grasp her hand. It was as much an unspoken agreement as it was him leaning on her. Counting on her. He steeled himself.
"If we have to get that mask to save this place...then we'll have to kill that kid. It needs to be done."
"I'll do it, Yuki!" She added gladly, turning back to the way they had come in from.
"Don't bother." He held up his diary, displaying what he had learned.
"The path we came in on has sealed itself. There's no point going that way." He turned to the Mask Salesman.
"So yes, we saw him." He answered the question.
"Right before we came in here. In fact...he encouraged us to come here. I thought it was just friendly urging but now I see." He looked over at Yuno.
"He needs to be saved, from himself. We'll kill him. Together."
"Thank you, Salesman. We'll just head into the city now, try to find your missing mask and the ones behind it. If nothing else, you can trust me." With that, he stepped forward followed by Yuno, pushing open the door to enter the city to find their prey.