There is something I was briefly considering but was unsure if it would be too much or if the possible timing would work. So thought I could ask for your input!
What if Vaggi was the one who killed Ribbit about a year before she had her wings ripped off?
The Exorcist had found a terrified purple rabbit sinner hiding amongst the rubble and right before she could put it down, another sinner- a green frog- had dived before her blade and deliberately shielded the other with it's own body.
Shaken, the soldier watches as the sinner coughs and refuses to let go of it- of her struggling... friend? Who was begging her to stop- to run away I'm not worth it- please don't die I'm so sorry-
Eyes wide behind her mask, the Exorcist backs away and pulls a large part the debris to cover the crator the sinners were hiding in. When questioned by the fellow soldiers about the screams she was leaving behind she brandishes the spear, still soaked in blood, and lies through her teeth: 'They are both mortally wounded and do not deserve the mercy of a quick death. Spend your time and energy elsewhere.'
They never think to question her. Why would they?
This self-sacrifice would be the first chip in the mental conditioning Vaggi had gone through like the other Exorcists (that sinners are barely even vermin let alone people) and eventually dominoes into her sparing the Cannibal Child the year after and being banished.
Vaggi may have struggled to earn Charlie's forgiveness, but that was more about the lying rather than the Genocide she participated in.
What about Vaggi having to face someone who survived her?
What if Vaggi had to face someone who had lost a loved one to not just to an Extermination she to part in, but directly to her blade?
Remember, Adam had acknowledged her as one of his best soldiers.
Response: @poiuytrewsdcvb
That is genius; that would give Jax even more reason not to open up and trust people if he ever finds out. I wonder if he will express genuine anger or simply laugh and try to downplay the situation, as he usually does when confronted with vulnerability. Perhaps he would say something like he doesn't really care about Ribbit and joke that he should be careful around Vaggi from now on. Maybe he would make Vaggi promise, like with Ragatha, to never mention Ribbit ever again with his chilling smile.