Melee weapon
Trigger: an enemy within 5 squares of this power's user reduces an ally to 0 or fewer hit points
Target: the triggering enemy
Attack: Strength + 1 vs. AC
Hit: "2[W] + Strength modifier damage."
Effect: "Before the attack, you can move to the nearest square from which you can attack the target.
"The ally can spend a healing surge and regains an additional 1d6 hit points for every opportunity attack you provoke while moving to the target."[MP:104]
Fearless rescue is a daily power available to warlords at 1st level.
CharOp Evaluation: Poor [Char-op Warlord]
The flavor for this is immaculate, and it's a decent attack- but the triggering condition is an ally dropping to zero HP, and you're a leader, and it's part of your job to prevent that from happening. Building around being bad at your job is not a winning strategy.