  This paper introduces the class of omnipotent dark energy (DE) models
characterized by nonmonotonic energy densities that are capable of attaining
negative values with corresponding equation of state parameters featuring
phantom divide line (PDL) crossings and singularities. These nontrivial
features are phenomenologically motivated by findings of previous studies that
reconstruct cosmological functions from observations, and the success of
extensions of $\Lambda$CDM, whose actual or effective DE density is omnipotent,
in alleviating the observational discordance within $\Lambda$CDM. As an
example, we focus on one embodiment of omnipotent DE, viz., the DE
parametrization introduced in Di Valentino et al. [Dark energy with phantom
crossing and the H0 tension, Entropy 23, 404 (2021)] (DMS20). By updating and
extending the datasets used in the original paper where it was introduced, we
confirm the effectiveness of DMS20 in alleviating the observational
discrepancies. Additionally, we uncover that its negative DE density feature,
importance of which was not previously investigated, plays a crucial role in
alleviating the tensions, along with the PDL crossing feature that the
parametrization presupposes. In particular, we find that there is a positive
correlation between the $H_0$ parameter and the scale ($a_p$) at which DE
density transitions from negative to positive, in agreement with previous
studies that incorporate this transition feature. For our full dataset, the
model yields $H_0=70.05 \pm 0.64$ (68% CL) relaxing the $H_0$ tension with a
preference of crossing to negative DE densities ($a_p>0$ at 99% CL), along with
the constraint $a_m=0.922^{+0.041}_{-0.035}$ on the scale of the presupposed
PDL crossing.
