Reading this reminded me of another series, for some reason. Maybe it's the power users and the post-apocalyptic world. Unfortunately I can't remember the name.
Many characters in the series were basically 'espers'. The met a being a white coat, and were transported to what turned out to be the future. The air in the future woke up their esp once they came back.
The mc's esper ability was terrifying and ate everything. Melcheses Door or Gate? It was a big black ball of devour.
Edit: Found it. It was called Psyren.