Plausible mass distribution of the total WD systems that are considered to be the progenitor of HdC stars. The contributions from different WD merger types are considered in all combinations between a hybrid, a CO, and a He WD (except for CO+CO and He+He). For illustration purpose, we separate the more massive channel made of a hybrid and a CO WD merger (blue) from all other ones (orange) listed in the legend. The overall distribution is bimodal.