Half a century since the concept of a cyborg was introduced, digital cyborgs, enabled by the spread of wearable robotics, are the focus of much research in recent times. We introduce JIZAI ARMS, a supernumerary robotic limb system consisting of a wearable base unit with six terminals and detachable robot arms controllable by the wearer. The system was designed to enable social interaction between multiple wearers, such as an exchange of arm(s), and explore possible interactions between digital cyborgs in a cyborg society. This paper describes the JIZAI ARMS’ design process, an interdisciplinary collaboration between human augmentation researchers, product designers, a system architect, and manufacturers, to realize a technically complex system while considering the aesthetics of a digital cyborg. We also provide an autobiographical report of our first impressions of using the JIZAI ARMS and use our findings to speculate on a model of potential social interactions between digital cyborgs.