I made an image of Kina's cyber arm. Largely for myself, so I could use it as a reference for future artwork.
The prosthetic arm itself is fully integrated with her nervous system, so her arm is just as functional as a regular arm. Furthermore, the prosthesis has several additional features. See the red dot on the forearm? It's a kind of gala projector (meaning it can display a hologram). And thanks to a built-in computer deep inside the prosthesis, there's a mini-computer similar to a modern smartphone. So she can use this gala projector to surf the internet or even make a phone call.
You might also have noticed the blue lines on her hand. They're there to show whether the current is flowing to her fingers, and also for aesthetic purposes.