He looked around after absorbing a lot of dark energy and found out the source of it. Yes, there was a tall tower on top of a building that was shooting this stuff to the air and was polluting it.
To be precise, it was filling the air with dark energy and was disrupting the energy balance of the nature.
Normally, everything in the world is supposed to have energy. Every living thing, that is.
However, even non-living things possess energy although they cant use it on their own. Though, they kept emitting it and absorbing it always while trying to maintain a constant balance.
So what would happen if that balance was broken?
Yes, the dark energy that was being liberated from their atmosphere wasn't something that was being created! As mentioned – Energy can neither be created nor be destroyed except in nuclear reactions where mass conversion occurs.
Hence, dark energy cannot be produced on its own nor can it appear out of nowhere.