  There has been growing interest in investigating properties of elementary
particles predicted by the standard model. Examples of such studies include
exploring their low-energy analogs in condensed matter system, where they arise
as collective states or quasiparticles. Here we show that a toolbox for
systematically engineering the emergent elementary fermions, i.e., Dirac, Weyl
and Majorana fermions, can be built in a single atomic system composed of a
spinless magnetic dipolar Fermi gas in a 3D optical lattice. The designed
direction-dependent dipole-dipole interaction leads to both the basic building
block, i.e, in-plane p+ip superfluid pairing instability and the manipulating
tool, i.e, out-of-plane Peierls instability. It is shown that the Peierls
instability provides a natural way of tuning the topological nature of p+ip
superfluids and thus transform the fermion's nature between distinct emergent
particles. Our scheme should open up a new thrust towards searching for
elementary particles through manipulating the topology.
