The time reaver was a dangerous weapon that turns one's perception of time slower. It was outlawed in many major galaxies according to the Tenth Doctor. (AUDIO: Time Reaver)
When the Vacintians found out that their planet was dying, they decided to use time reavers to see their sunset much longer before they die. But Cora, a Vacintian, stole the time reavers and tried to sell it in Calibris, believing that others could use it for good. (AUDIO: Time Reaver)
A time reaver can be converted into a bomb in order to scatter its effects.
It was found out that the time reaver has a different effect on Time Lord body when the Doctor fired all time reaver to himself, which is supposedly equivalent to a number of centuries. However, the doctor recovered from its effects just after a few minutes. (AUDIO: Time Reaver)