The user can make others age in reverse ergo making them younger. Some make them age backwards the same rate as the did forwards and some can make them age backwards very quickly by going about a year per second back. Some can put them on an automatic aging process making them become younger and younger at a certain speed until they go from children to toddlers to babies to fetuses to sperm to not existing. Some can recover their original age and revert them to their real age.