>>1781656
Just a guitar. It's established that typical mana is a power source for a lot of things in the setting from lights to weather controls, both in ancient and modern times. Picrel for example is an engineer who uses a mana cannon to shoot out fiery bullets and high-powered beams.

No, she does not have an amp or a pedal. The "guitar" itself is uncharacteristically loud compared to contemporary instruments, to the point that it can hurt other living beings if she's not careful.