  We theoretically study the interplay between bulk Weyl electrons and magnetic
topological defects, including magnetic domains, domain walls, and
$\mathbb{Z}_6$ vortex lines, in the antiferromagnetic Weyl semimetals \mnsn\
and Mn$_3$Ge with negative vector chirality. We argue that these materials
possess a hierarchy of energies scales which allows a description of the spin
structure and spin dynamics using a XY model with $\mathbb{Z}_6$ anisotropy. We
propose a dynamical equation of motion for the XY order parameter, which
implies the presence of $\mathbb{Z}_6$ vortex lines, the double-domain pattern
in the presence of magnetic fields, and the ability to control domains with
current. We also introduce a minimal electronic model which allows efficient
calculation of the electronic structure in the antiferromagnetic configuration,
unveiling Fermi arcs at domain walls, and sharp quasi-bound states at
$\mathbb{Z}_6$ vortices. Moreover, we have shown how these materials may allow
electronic-based imaging of antiferromagnetic microstructure, and propose a
possible device based on domain-dependent anomalous Hall effect.
