  Chirality causes diverse phenomena in nature such as the formation of
biological molecules, antimatters, non-collinear spin structures, and magnetic
skyrmions. The chirality in magnetic materials is often caused by the
noncollinear exchange interaction, called the Dzyaloshinskii-Moriya interaction
(DMI). The DMI produces topological spin alignments such as the magnetic
skyrmions and chiral domain walls (DWs). In the chiral DWs, the DMI generates
an effective magnetic field $H_{DMI}$, resulting in a peculiar DW speed
variation in the DW creep regime. However, the role of $H_{DMI}$ over the
different DW-dynamics regimes remains elusive, particularly due to recent
observation of distinct behaviors between the creep and flow regimes. We hereby
demonstrate experimentally that the role of $H_{DMI}$ is invariant over the
creep and flow regimes. In the experiments, the pure DMI effect is quantified
by decomposing the symmetric and antisymmetric contributions of the DW motion.
The results manifest that the antisymmetric contribution vanishes gradually
across the creep and flow regimes, revealing that the symmetric contribution
from $H_{DMI}$ is unchanged. Though the DW dynamics is governed by distinct
mechanisms, the present observation demonstrates the uniqueness of the DMI
effect on the DWs over the creep and flow regimes.
