The focal point of this article involves questioning what being human means with regard to the web of dynamic relationships with a number of agencies, including but not limited to robotic bodies, which point to the technological evolution of humanity. The novel dynamics in robotization have paved the way for certain anthropocentric anxieties to lose human agency vis a vis robotic bodies by gaining greater agency to impact their environments. This article aims within the framework of posthumanism to overthrow this anthropocentric anxiety and to shatter the myth of human superiority that was formulated especially in accordance with the Enlightenment’s emphasis on the privilege of reason. By acknowledging the material and discursive interconnectedness in the process of making meaning, posthumanism has become the critical confuting of the anthropocentric positioning of humans as implemented by the humanist and Enlightenment discourses and ideas, hence challenging Cartesian dualism. Posthumanism revisits and redefines what being human means by opposing the separation of body and mind in the form of human existence and by challenging humans’ assumed superior and distinctive position and exceptionalism. In so doing, posthumanism also further criticizes and blurs ontological and epistemological categorizations by highlighting the inevitable and inseparable relations humans have with other agencies such as nonhuman animals, plants, elemental bodies, robotic bodies, toxic formations, seasons, radiation, continental policies, and social and cultural formations. Although posthumanism is not limited to only robotic redefinitions of what being human means, robotization still plays a key role in showcasing humans’ redefinition through posthumanist inquiries. From this perspective, this article aims to analyze how robots prevail in modern society, whether in the workforce or in artistic areas such as performance studies. This article exemplifies two famous robot musicians to trace the beginnings of the robotic presence in the music industry. The first example involves Shimon, a skilled musician developed in 2017 by Prof. Gil Weinberg at the Georgia Institute of Technology for a robotic music project. The second one involves Hatsune Miku, a virtual mixture of the vocal artist Saki Fujita, the anime designer Kei, and Crypton Future Media, Inc., as these two examples already show how robotic bodies have started to prevail in performance art. In addition to these two nonhuman bodies that are famous in the music industry, this article also draws attention to robot actors, in particular to the Seinendan Theatre Company and Osaka University Robot Theatre Project. This article also provides some robot theatre examples within this project, including La Métamorphose (2014) as a co-production of Japanese and French performance art, Sayonara (2013), and I, Worker (2013), all of which were written and directed by Oriza Hirata. Though not included in the above-mentioned robot theatre project, Francesca Talenti’s The Uncanny Valley (2013) and Rimini Protokoll’s Uncanny Valley (2022)  are other examples of robot theatre. All these plays distinctively illustrate the dominance of robot actors on theatre stage as a counterpart to their human colleagues. In addition to these robot performers, the article also acknowledges the conceptual insertion of robotic and virtual bodies into plays long before the material introduction of robotic bodies on stage. A quotation from Caryl Churchill’s Love and Information (2012) illustrates how virtual bodies have been conceptually discussed in dramatic plays. This example also underlines the clash between the virtual/robotic embodiment and physical embodiment that appears in the dichotomy between organic and inorganic bodies. This dichotomy underlines humanity’s ancient fear about losing their essential and organic existence to inorganic machines. This fear is at the heart of blurring the line between life and death, thus indicating humanity’s obsession with defining life in human terms. By granting cogency to the posthumanist redefinition of humanity, this article hints at humanity’s evolution with robotic bodies. American soldier Craig Lundberg showcases how a human body can evolve through constant interaction with robotic and technological extensions and insertions. Upon taking all these examples and theoretical discussions into consideration, this article redefines and revises what being human means using post-humanist ideas with references to a number of robot theatre performers.