As constraints on dark matter from direct detection, indirect detection and collider experiments become more stringent, many models of electroweak-scale dark matter must now exhibit very specific mass relations in the dark sector to remain viable. For instance, the dark matter may be close in mass to another state, permitting coannihilation with or phase-space suppressed annihilation to the other state. Alternatively, the dark matter mass may be approximately half that of a resonance. We discuss the idea that such mass relations could arise due to IR-attractive ratios in renormalization group equations. Achieving a particular ratio requires specific dark matter gauge charges or interactions, leading to predictions about the dark matter properties. Furthermore, additional states with masses comparable to the dark matter mass may be necessary, potentially giving rise to novel phenomenology. We explore this idea in the context of dark matter charged under a new gauged U(1) that kinetically mixes with the Standard Model hypercharge.