  The aim of this paper is to extend the notion of all known quasi-Einstein
manifolds like generalized quasi-Einstein, mixed generalized quasi-Einstein
manifold, pseudo generalized quasi-Einstein manifold and many more and name it
comprehensive quasi Einstein manifold C(QE)$_{n}$. We investigate some
geometric and physical properties of the comprehensive quasi Einstein manifolds
C(QE)$_{n}$ under certain conditions. We study the conformal and conharmonic
mappings between C(QE)$_{n}$ manifolds. Then we examine the C(QE)$_{n}$ with
harmonic Weyl tensor. We investigate geometric and physical properties of the
comprehensive quasi Einstein manifolds C(QE)$_{n}$ under certain conditions. We
define the manifold of comprehensive quasi-constant curvature and proved that
conformally flat C(QE)$_{n}$ is manifold of comprehensive quasi-constant
curvature and vice versa. We study the general two viscous fluid spacetime
C(QE)$_{4}$ and find out some important consequences about C(QE)$_{4}$. We
study C(QE)$_{n}$ with vanishing space matter tensor. Finally, we prove the
existence of such manifolds by constructing non-trivial example.
