The following is an adaptation of the Avenger class made by Hasturtimesthree over in the GLoG server on discord. Check it out if you haven't and maybe say hi if you do.
[A]: Target, Background, Collateral
[B]: Grit, Commit
[C]: Spirit of Vengeance
[D]: Mastery of Determination
Choose someone who unjustly wronged you; they should be powerful enough that it may take years to achieve revenge. You may choose multiple targets, if you so desire.
Choose or roll to see how you were wronged, and gain the selected skill:
Imprisonment: Stealth - You can vanish from the scene at any time, only to appear as if
from nowhere at an opportune moment.
Murder: Scrutiny - You can always tell when someone harbors ill-will towards you.
Slander: Rumor-sniffing - while gathering rumours, either through corroboration
and communication, you can remove 1d3 false rumours at random.
Marooning: Navigation - No matter where you are, you always know your bearing to
one specific location.
Exploitation: Scrounging - If you dig around for 10 minutes, you can always find a
substitute, makeshift, or jury-rigged basic tool that’ll last one use.
Abuse: Deception - As long as you speak around the truth, nobody will ever
suspect you may have misled them.
Record the names of those you unjustly harm in the course of your vengeance, and how.
Once your vengeance is complete, lose all your Struggler templates (except your [D] template), as you no longer need them, and roll 1d20. If the result is greater than the number of collateral casualties you have recorded, nothing happens. Otherwise, the corresponding Collateral casualty is now a Struggler, targeting you, with half your XP. If this is implausible, choose another such. If they are dead, then they in fact miraculously survived.
You can go without sleep or food for a number of days equal to your Build score before collapsing from exhaustion.
Before making an attack roll, you can call a result on the Hit Location Table, if you roll the called result, you can make a second attack for free against the same target.
Spirit of Vengeance
You attract the attention of a random Angel, they may occasionally help you achieve your vengeance free of charge, but more often they’ll ask a price. They will be inherently manipulative and deceptive with their goals. If you wish, you may add them to your Targets, and they will be none the wiser.
Mastery of Determination
Over the course of a downtime, you achieve a breakthrough in some field. Perhaps you achieved mastery as a duelist, or learned powerful magic. Choose any template from another available class or come up with one of your own, and gain its benefits.