On first glance, this sword is unassuming. It consists of a simple blade, scarred and dulled with age, attached to a plain, unornamented hilt. Yet worked into the hilt is a powerful holy relic, and, in the right hands, this weapon is a device of truly awesome power. Many legends tell of otherwise ordinary men bringing this weapon to bear against the darkest of demons and coming out victorious. This sword is named after the prized D&D weapon, but it draws inspiration from fictional examples such as Lightbringer (from A Song of Ice and Fire) and (especially mechanically) from the Swords of the Cross (from the Dresden Files)
The holy avenger provides a great boon to its wielder:
[li]The +1 Ob penalty from superficial wounds is negated
[/li][li]+3D to the Sword skill
[/li][li]Grants the wielder the Aura of Holiness trait
[/li][li]The sword itself is Grey shade, and uses the superior quality Long Sword stats
In addition, if the weilder is Faithful, the sword may grant an advantage die to Faith tests where thematically and narratively appropriate
Furthermore, the true enemies (this refers to the supernatural enemies, not heretics or apostates) of the faith cannot abide the touch of this sword. They take an additional pip of damage from the weapon, and suffer a superficial wound if they try to grasp the weapon. If appropriate, the sword counts as a spirit weapon against its enemies.
Finally, the weapon itself bears stigmata. This should be appropriate to the faith: the sword of a fire god will burn with holy fire, while that of a sun god might glow with a brilliant divine light. These stigmata are normally only present when in active combat, though the sword’s weilder can call upon them at will. Furthermore, these stigmate do not negatively affect the weilder in any way, though they may impose a penalty on others.
Though it has great power, the sword is also profoundly limited (though, a true believer would not see it as such). The bearer of the sword must in action be a paragon of virtue. Should the sword be used for an action (or inaction) that contravenes any of the core principles of the faith, its power is lost. Furthermore, in order to use the sword, the player must possess a belief that specifies how they will use the sword (i.e., for what goal, or to uphold what principles). Using the sword to contravene this belief also causes the power of the sword to fade. Once this happens, the sword loses all benefits associated with it until it is reaffirmed (see the below section). During this time, it counts as a black shade weapon, and enemies of the faith may touch it without consequence.
Should the belief powering the sword be lost, the bearer has put down the sword and moved on: he has fufilled his purpose in using it, and is passing it on to someone who needs it more. It is unlikely (though not impossible) that they will be called on to wield the sword again.
The particulars of what actions are permitted while using the sword are dependent on the faith in question, and should be discussed between the GM and players before it is introduced. A sword belonging to a Christianity-like faith would have similar, if not identical, restrictions as the Swords of the Cross from the Dresden Files (i.e., cannot be used against innocents, those who have surrendered, or in defense of sin). On the other hand, a sword belonging to an Aztec-like faith would likely require that it be used on innocents (i.e., human sacrifice) in order to function properly. Other requirements may be present as well: the sword for an Islam stand-in might require it’s bearer to bring the sword on the faith’s Hajj equivalent annually.
Reaffirming the Sword:
Though the power of the sword may be lost, all hope is not. Once any physical damage to the sword is repaired, a Minor Miracle may be invoked over the blade to return it to it’s former status. There is, however, an alternative path. A new swordbearer may simultaneously reaffirm the blade and find their calling as a paladin of the faith: by using the sword to fufill (i.e., receive Persona or Deeds points for) a Belief that would fufill the Belief requirements of the sword. Doing so instantly returns the blade to its former glory.
The Holy Avenger in-game
Narratively speaking, it’s unlikely that a Holy Avenger will find it’s way to a character who does not already possess a belief fit to allow it’s use. In a way, havng such a belief in a universe with a Holy Avenger is a way to signal the GM that you want the weapon to fall into your hands.
The easiest way to introduce a weapon is to have an NPC Paladin be killed, and hand off the blade to the player, or to place the blade in the possession of the enemies of the faith, and have the player reaffirm the blade in play. Either way, the Holy Avenger is a powerful artifact, and it should not be handed out lightly.