A pluriversal encounter that includes interlocutors from other ways of knowing and being requires recrafting how we commonly approach ontology in IR. Our shared ontological register only acknowledges separation as the fundamental existential assumption, and not all lifeways depart from this assumption. The article prods us to move beyond considering ontology as the study of being, a more substantialist reading, to include other fundamental existential commitments so that we can address how distinct presuppositions shape and are shaped by how we perceive and engage existence. With this reorientation, the article first establishes how even relational approaches in the discipline, including variations of constructivism, poststructuralism, and new materialism privilege separation as the primordial condition of existence to the exclusion of any other option. A conceptual toolset is then elaborated to examine how a singular commitment to separation constitutes an ontological parochialism that enforces reductionism, exclusion, and domination towards lifeways that embrace the interconnection as fundamental existential commitment. Even though more effective engagement across pluriversal worlds would be crucial for developing more complex tools for confronting the current planetary crisis, the discipline's reductionist concept of ontology itself keeps us quite far from effectively being able to engage in such an exchange.