The Blade of Mercy is name held by a Great sword wielder in the tenth crusade.
Power Level
While not much has been revealed about the names power as the current holder is extremely young the Blade of Mercy has fought the Squire wearing the winter mantle and survived although with assistance of others. Although extremely fast the necessity of using large weapons and specifically great swords means that the named is best suited for mid-range combat keeping an enemy at a distance where the sword is most effective. When the weapon is broke the wielder must still rely on the weapon meaning reliance on this weapon can become a handicap preventing the name in specializing in any other combat besides great sword combat.
Role
The name seems to be tied into wielding large bladed weapons. The mercy aspect 'could' be tied in to the fact that the named will kill to lessen the pain of another or to in fact end the suffering of others. Using violence as an act of mercy.
Special Abilities
The name grants increased proficiency with large bladed weapons granting proficiency in combat. The name also shown aspects that improve an individuals constitution preventing damage should anyone bypass there sword swings.