  We revisit the case of scalar dark matter interacting just gravitationally
with the Standard Model (SM) particles in an extra-dimensional Randall-Sundrum
scenario. We assume that both, the dark matter and the Standard Model, are
localized in the TeV brane and only interact via gravitational mediators,
namely the graviton Kaluza-Klein modes and the radion. We analyze in detail the
dark matter annihilation channel into two on-shell KK-gravitons, and contrary
to previous studies which overlooked this process, we find that it is possible
to obtain the correct relic abundance for dark matter masses in the range [1,
10] TeV even after taking into account the strong bounds from LHC Run II. We
also consider the impact of the radion contribution (virtual exchange leading
to SM final states as well as on-shell production), which does not
significantly change our results. Quite interestingly, a sizeable part of the
currently allowed parameter space could be tested by LHC Run III and by the
High-Luminosity LHC.
