While God used good unfallen angels primarily to adversely affect earth, its environment, and humanity's social
conditions during this period of Judgment, fallen angels were allowed to indulge in their evil.
When the sixth trumpet sounds, the unfallen angel is authorized to release the four bound angels at the Euphrates
River (Rev 9:13-14).
When the Bible speaks of confined or bound angels, it is always in the context of fallen evil
angels (Luke 8:26-31;
Matt 8:28-32; 2 Peter 2:4;
These four bound angels were limited to kill 33% of the world's population.