Aging
The trio just walked out of the city unscathed.
But on their way, they killed as many people as they came. After a while, the organization members did get some sense and didn't come forward to fight them.
The trio just went to the nearest branch to await the results.
They just sat there without doing much. They just planned for their next target which is going to be much more similar and in fact easier than this.
The cube that was planted in the middle of the city started spreading out different elemental energies. Fire, death, and earth are elemental energies all together.
The elemental fire energy has the highest level of concentration than the rest of the energies. This completely evaporated all the moisture in the surroundings.