  With the motivation of simultaneously explaining dark matter and neutrino
masses, mixing angles, we have invoked the Type-II seesaw model extended by an
extra $SU(2)$ doublet $\Phi$. Moreover, we have imposed a $\mathbb{Z}_2$ parity
on $\Phi$ which remains unbroken as the vacuum expectation value of $\Phi$ is
zero. Consequently, the lightest neutral component of $\Phi$ becomes naturally
stable and can be a viable dark matter candidate. On the other hand, light
Majorana masses for neutrinos have been generated following usual Type-II
seesaw mechanism. Further in this framework, for the first time, we have
derived the full set of vacuum stability and unitarity conditions, which must
be satisfied to obtain a stable vacuum as well as to preserve the unitarity of
the model respectively. Thereafter, we have performed extensive
phenomenological studies of both dark matter and neutrino sectors considering
all possible theoretical and current experimental constraints. Finally, we have
also discussed a qualitative collider signatures of dark matter and associated
odd particles at the 13 TeV Large Hadron Collider.
