Diachronic emergence has recently been characterised as transformation. This aims to capture the thought that the entities that emerge are radically new or different. Transformation is hence closely linked with a central (but rarely raised) challenge for all emergentists: how to account for the identity and individuation of entities involved in emergence. With this challenge in view, I develop and probe four interpretations of transformation: addition, replacement, fusion, and transubstantiation. Of those, transubstantiation provides the most plausible response to the challenge (...) about identity. Accordingly, diachronic emergence is a transformative process whereby an individual passes from one primary kind to another. (shrink)