Impact of the [C II]$_{158 \mu \text{m}}$ luminosity scatter on the
  line-intensity mapping power spectrum from the EoR
  Redshifted [C II]$_{158 \mu\text{m}}$ line-intensity mapping (LIM) of the
Epoch of Reionization (EoR) with ongoing and upcoming experiments like the
CONCERTO, TIME and FYST, is a new tool to constrain the role of the early
galaxies in reionization. We expect statistics, e.g., the power spectrum of the
LIM signal to be detectable by these experiments, which will help us understand
the large-scale distribution and astrophysical properties of the [C II]$_{158
\mu\text{m}}$ line emitters. In this work, unlike a simple semi-analytical
approach, we derive the [C II]$_{158 \mu\text{m}}$ line-luminosity scatter,
which arises from various ongoing astrophysical processes under varied
environments inside individual galaxies, from a hydrodynamic and radiative
transfer simulation of galaxies, to interpret its impact on the power spectrum.
We compare the luminosity scatter scenario with best-fit relations obtained
from mean and most probable $L_{\text{[CII]}}$ values and find that in both
cases, along with a slight, unavoidable diminishing of the luminosity-weighted
halo bias, the clustering (large-scale) power spectrum is impacted
significantly, in addition to the shot-noise component. In the latter case, the
power spectrum is enhanced by a factor of $\sim 2.7-2.9$ for $0.1 \leq k \leq
1\, \text{Mpc}^{-1}$ (at $z=6$); we present this alternative approach to
interpret this enhancement in the clustering power in conjunction with a simple
analytical model. It is crucial to appropriately model and take line-luminosity
scatter into account to interpret the [C II]$_{158 \mu\text{m}}$ power spectrum
from future observations.
