Characteristic masses and evolution in the HRD for the VMSs. Left panel: Final mass (triangles) and mass of the CO core (diamonds) at the end of core helium-burning for non-rotating (black) and rotating (red) VMS models. The grey line corresponds to y = x. Right panel: Evolutionary tracks in the HRD, colour-coded according to the surface enrichment of nitrogen log(N/H [numb.]) + 12. Each pair of (non-rotating, rotating) tracks is labelled with the initial mass of the models. The circles and crosses respectively indicate the beginning and end of each central burning phase (black: hydrogen, green: helium, red: carbon). The non-rotating tracks are the ones that remain purple during the MS.