Deflect Melee

Deflect Melee 'is a prayer which is similar to Protect from Melee, except it has a chance of deflecting some damage at its source. This is considered to be one of the most useful prayers in the game, along with Protect from Melee, as a great majority of Runescape's players and monsters uses melee. This prayer can be used as a high-level alternative to Protect from Melee, and provides a 60% damage reduction against other players in PvP scenarios, rather than the 40% offered by the standard protection prayer. In order to use this prayer you must have the Ancient Curses activated which requires completion of The Temple of Senntisten quest

The deflection curses are a primary reason for players to switch from the normal prayer set to the curses, as they have a slower drain rate than their respective protection prayers, commonly known as "pray from melee, range and mage".

The Damage reflected seems to be dependent on how much the attack would have done prior to be being blocked by the prayer:

10+ = 1

20+ = 2

30+ = 3

40+ = 4

50+ = 5

60+ = 6

etc etc.