Is a World Drop from high level mobs (66-70). There has been much debate on this enchant on how it is best used. Some melee dps players have tried as well as tanks. The proc will heal everyone in the "party", which would mean only the 5 people/pets in your group, (not whole raid) and only those within 30 yards. The general belief is that the healing proc generates threat as a healing spell like any other heal, but threat meters do not conclusively confirm it. Consensus has not been reached on battlemaster's threat generation. If it does cause threat, for endgame it is negligible even if the entire party is healed. (A good proc heal is equivalent threat to an average attack or heal at level 70 in poor gear.)