  A macroscopic effect can be induced by a local non-Hermitian term, when it
manifests simultaneously level coalescence of a full real degeneracy spectrum,
leading to exceptional spectrum. In this paper, we propose a family of systems
that support such an intriguing property. It is generally consisted of two
arbitrary identical Hermitian sub-lattices in association with unidirectional
couplings between them. We show exactly that all single-particle eigenstates
coalesce in pairs, even only single unidirectional coupling appears. As an
application, we study the dynamic magnetization induced by complex fields in an
itinerant electron system. It shows that an initial saturated ferromagnetic
state at half-filling can be driven into its opposite state according to the
dynamics of high-order exceptional point. Numerical simulations for the
dynamical processes of magnetization are performed for several representative
situations, including lattice dimensions, global random and local impurity
distributions. It shows that the dynamic magnetization processes exhibit
universal behavior.
