  We provide a detailed study of reheating in the kination regime where
particle content is created by gravitational production of massive scalars
mutually interacting with a massless scalar field. The produced particles
subsequently decay into massless particles eventually reheating the Universe.
We aim for a more precise picture using Boltzmann equations and decay rates
obtained by methods of quantum field theory in curved spacetime. By numerical
calculations it is found that after inflation the Universe ends up being
dominated by ordinary matter for a while before the radiation dominated era.
The reheating temperature itself is found to be in the $10^6-10^{12}\
\text{GeV}$ regime.
