The prevailing knowledge of dwarf galaxies hosting wandering massive black holes (MBHs) have substantially increased with the recent discovery of nearby low masses galaxies hosting off center MBHs. The new finding is consistent with predictions made earlier from computer simulations. We investigate mergers of dwarf-dwarf systems with at least one of them harboring an off center MBH using high resolution, cosmological, zoom-in simulations. The work involved first tracking the location of the wandering MBHs from the center of their host galaxies over time since the Big Bang. Predictably, they count for half of the existing massive black holes in all the four simulations. An interpretative reason for this is merging dwarf-dwarf galaxies, which causes the black holes to leave the center and sometimes do not return due to the number of mergers they undergo in their life time.