The purpose of this study is to clarify the ‘ultimate uniqueness’ of human character(人性) amidst the rapid advancement of Artificial Intelligence (AI) and to establish the direction of character education accordingly. To this end, a comparative philosophical approach was employed to cross-examine the ‘Theory of the Sameness and Difference of Human and Animal Nature(人物性同異論)’ of Joseon Confucianism and modern sociobiological discourse. The results suggest that virtue (德性) should be regarded as an intrinsic characteristic that secures the uniqueness of human character. Next, to examine the boundary between AI and human character, the essence of human character is redefined not as a sum of virtues but as ‘relationship’ between oneself and others. Through this, a framework is presented to distinguish between the realm of ‘post-uniqueness’, where AI and humans overlap, and the realm of ‘ultimate uniqueness’ based on self-reflection, authenticity, and practical virtue. While AI’s actions demonstrate a ‘simulated relationality’ formed by external purposes and data, humans can establish genuine relationships by integrating self-understanding and responsibility within the ‘horizon of significance,’ thereby realizing moral subjectivity in the process. Based on this analysis, this study argues that the direction of future character education should aim to further develop the uniqueness of human character and establish desirable relationships rooted in authenticity. Finally, this study redefines the goals of character education as the ‘establishment of subjectivity’ and the ‘formation of genuine relationships,’ and proposes specific educational methods to implement them.