Lives is a manga that tells the story of meteorites that hit the Earth and seem to kill people. But some of those people killed find themselves alive again in a strange world, where some of them transform into various creatures. Some are able to transform back into a human.
A naked woman with angel wings flies over and informs them she created this world, and they had to fight to survive, she wanting to test natural selection. One who gave up his humanity entirely to become just a beast of battle, she did turn into a small insect creature.
Some have the overwhelming urge to eat other humans.