Even though she looked down on Silver Lamp for wasting her thoughts on things like this, she had to admit that Silver Lamp was genuinely good to Ash.
Ash might know, or might not know. But he certainly wanted to use such a promise to win her over, and use so-called trust to make a thousand-year Demigod loyal to him. Since this is the case...
Vishi's body became softer, and her voice more pitiable: "Since everyone hates me, it seems the only one I can rely on is you, Master."
"No, you can't rely on me either."
Ash said, "All your excuses, I won't even believe a punctuation mark."
Vishi was stunned.
Ash: "If you're guilty of murder, then you're guilty of murder. If you accuse the Sword Maiden of framing you, then that's an added crime."
Vishi, too shocked, spoke with a tone of anxiety: "But if I use the ruby chain to swear I'm not lying—"
