  Motivated by recent experimental progress on various cluster Mott insulators,
we study an extended Hubbard model on a breathing Kagom\'{e} lattice with a
single electron orbital and $1/6$ electron filling. Two distinct types of
cluster localization are found in the cluster Mott regime due to the presence
of the electron repulsion between neighboring sites, rather than from the
on-site Hubbard interaction in the conventional Mott insulators. We introduce a
unified parton construction framework to accommodate both type of cluster Mott
insulating phase as well as a trivial Ferm liquid metal and discuss the phase
transitions in the phase diagram. It is shown that, in one of the cluster
localization phases, the strong inter-site repulsion results into locally
metallic behavior within one of two triangular clusters on the breathing
Kagom\'{e} lattice. We further comment on experimental relevance to existing
Mo-based cluster magnets.
