  We propose an extension of the standard model with Majorana-type fermionic
dark matters based on the flatland scenario where all scalar coupling
constants, including scalar mass terms, vanish at the Planck scale, i.e. the
scalar potential is flat above the Planck scale. This scenario could be
compatible with the asymptotic safety paradigm for quantum gravity. We search
the parameter space so that the model reproduces the observed values such as
the Higgs mass, the electroweak vacuum and the relic abundance of dark matter.
We also investigate the spin-independent elastic cross section for the Majorana
fermions and a nucleon. It is shown that the Majorana fermions as dark matter
candidates could be tested by dark matter direct detection experiments such as
XENON, LUX and PandaX-II. We demonstrate that within the minimal setup
compatible with the flatland scenario at the Planck scale or asymptotically
safe quantum gravity, the extended model could have a strong predictability.
