  We study bulk fermion fields in various multi-brane models with localized
gravity. The chiral zero mode that these models support can be identified as a
right-handed sterile neutrino. In this case small neutrino Dirac masses can
naturally appear due to a localization of the bulk fermion zero mode
wavefunction, in an analogous way to graviton, without invoking the see-saw
mechanism. The conditions and the options for localization are discussed in
detail. It is shown that, considering a well motivated five dimensional mass
term, the localization behaviour of this mode can resemble the graviton's at
least in a region of the parameter space. As a result, the ''+-+'', ''++''
models can support, in addition to the ultralight graviton KK state, an
ultralight localized and strongly coupled bulk fermion KK mode. We find that
there are severe constraints on the parameter space of ''+-+'' and ''++''
models if the neutrino properties resulting from this light fermion state are
to be reasonable. Furthermore, in the case that also the Bigravity scenario is
realized the above special KK mode can induce too large mixing between the
neutrino and the KK tower sterile modes restricting even more the allowed
parameter space.
