To improve upon the eb-MBE, we recently proposed a density-based many-body expansion (db-MBE), which is motivated by the observation that the MBE of the electron density [Eq. ( )] seems to converge faster than the MBE of the total energy [Eq. ( )]. The db-MBE represents a generalization of subsystem DFT and can be formulated as an ONIOM-style multilevel approach, in which the eb-MBE serves as the high level, while orbital-free DFT is used as the low level, i.e.,