Objective: Narcissism can manifest in grandiose and vulnerable patterns of experience and behavior. While largely unrelated in the general population, individuals with clinically relevant narcissism are thought to display both. Our previous studies showed that trait measures of grandiosity and vulnerability were unrelated at low-to-moderate levels of grandiose narcissism, but related at high levels. Method: We replicate and extend these findings in a preregistered individual data meta-analysis (“mega-analysis”) using data from the Narcissistic Personality Inventory (NPI)/Hypersensitive Narcissism Scale (HSNS; N = 10,519, k = 28) and the Five-Factor Narcissism Inventory (FFNI; N = 7,738, k = 17). Results: There was strong evidence for the hypothesis in the FFNI (β _{Grandiose < 1 SD} =.08, β _{Grandiose > 1 SD} =.36, β _{Grandiose > 2 SD} =.53), and weaker evidence in the NPI/HSNS (β _{Grandiose < 1 SD} =.00, β _{Grandiose > 1 SD} =.12, β _{Grandiose > 2 SD} =.32). Nonlinearity increased with age but was invariant across other moderators. Higher vulnerability was predicted by elevated antagonistic and low agentic narcissism at subfactor level. Conclusion: Narcissistic vulnerability increases at high levels of grandiosity. Interpreted along Whole Trait Theory, the effects are thought to reflect state changes echoing in trait measures and can help to link personality and clinical models.