I will present the results from the supernova cosmology key paper with the completed Dark Energy Survey. With a brand new sample of ~1500 type Ia supernova, which approximately quintuples the cosmology-quality high-redshift (z > 0.5) supernovae in the literature, we find tight constraints on dark energy and dark matter. In addition to the standard cosmological analyses I will present our explorations of the deeper implications into the nature of dark energy such as testing its time variability (and maybe even measuring cool effects like cosmological time dilation). I’ll introduce a new parameter Q_H (in analogy to S_8 for lensing) that takes into account the degeneracy direction in the w-Omega_M plane for SNe. Finally, I’ll show to what extent our published Hubble diagram is cosmological model independent, and how to use the data to test your own favourite cosmological model.