It no longer exists, unless you know a way to change energy to matter.
Where do you think all this matter came from?
Entropy will eventually result in a universe with no energy and no increase in mass.
Ever increasing entropy results in a universe with no energy
that can be converted to work. There will still be energy. Plenty of it. Near the end, the universe will first go through a state where most of its matter is locked up in black holes. As those black holes evaporate, all that will be left behind eventually is a sea of isotropically distributed photons and leptons of an average temperature asymptotically tending to zero in time. That's energy - but it can't produce any useful work at all. The only "feature" of such a universe with any useful meaning would be its temperature, which would get closer and closer to zero over time, but never get there.