Posthuman feminism grows out of interdisciplinary discourse exploring relational metaphysics. It is set apart from other approaches in the broader ontological turn by its central ethical claim: by actively forming kinship or alliances among human and non-humans, we can overcome major challenges of today's world and create a better future. Archaeologists and anthropologists are well situated to investigate this claim, as we already work with worlds unstructured by western dichotomies. This paper explores one such past world—Iron and Viking Age Scandinavia—to ask how alternative more-than-human relationships may work in practice. Specifically, we examine the relations among swords, animals, houses and humans in the first millennium ce, assessing ethical commitments within Butler's framework of grievability. We argue that the picture that emerges is fundamentally relational and unfamiliar, with complex articulations of bodies and personhood criss-crossing human–object divides; however, the ethical commitments of this world leave us deeply uncomfortable. Thus, although we welcome posthuman feminism's call to ontological openness, we caution against too easy an association between more-than-human kinship and ethical projects.