Evil Rogue / Archivist PC Background in a good Convent Hooks

[Reprimand]

So I'm playing a rogue / archivist who is working with a cult of vecna I was given a mission by Vecna to lead a group of paladins who have pretty much turned into our current antagonists to a cave and turn the hunters into the hunted.

My character has a bit of a philosophy motif and I wanted to change my backstory to once being a mage hunter of tyr (the god of the paladins).
To invoke that juicy "We're not so different you and I," Trope.

My character started at 4th level and took levels in archivist after coming to the campaign so the mage hunter origin gives me a sort of previous familiarity with magic and piety as well as the spenders of
education i.e. monastery library.

I wanted a good reason to be distrustful or have a falling out with this origin to sort of demonstrate the hypocrisy of the supposedly justice filled world tyr seeks to create or the cruelty caused by such a crusade no matter the pure intentions.

Despite my character's scholarly aspects I really wanted to stay away from invoking the whole reading a tome from the forbidden section of the library since it's kind of overused.
or the Crusader leader is actually possessed or actually super evil.

EDIT: I'm trying to come with with hooks that would cause a mage hunter to fall from grace or find faults with his own place in Tyr's worldview that I can expand on. One to two sentence hooks is basically all I'm looking for.

This character really adheres to a scholar mindset bonus points for anything going along with this!

[Spore]

Criticizing a LG government/philosophy is easier said then done but you can always reduce it to its lawful part and divide it away from the actual good intentions. Evil people hide behind laws that exist and laws they created. And there is nothing a LG paladin can do against it or risk loosing their ways (read: powers).

Tyr hates trickery and deceit even if it could help save lives. Tyr would send a dozen men to their deaths than to let one evil doer escape. And at their very heart, any Tyr follower is a zealous crusader, willing to murder others over their beliefs.

Even if the paladin _tells_ you the creature is evil and must be smitten, what tells you the paladin speaks true? Are they always sure a bystanding arcanist has not cast misdirection to make his lieutenant die for his cause, allowing the villain to be imprisoned and eventually escape?

Also you could just use the events of the Spellplague.Tyr killed Helm by mistake. Would a truly good god do that? Tyr died and got ressurected. Who says he actually wasn't "damaged"? Who says this cult is not following an imposter? I mean have you heard about a god being simply revived? Even in a world where you can bring people back from the dead, bringing a god back sounds a bit like you're lying.

[Reprimand]

Criticizing a LG government/philosophy is easier said then done but you can always reduce it to its lawful part and divide it away from the actual good intentions. Evil people hide behind laws that exist and laws they created. And there is nothing a LG paladin can do against it or risk loosing their ways (read: powers).

Tyr hates trickery and deceit even if it could help save lives. Tyr would send a dozen men to their deaths than to let one evil doer escape. And at their very heart, any Tyr follower is a zealous crusader, willing to murder others over their beliefs.

Even if the paladin _tells_ you the creature is evil and must be smitten, what tells you the paladin speaks true? Are they always sure a bystanding arcanist has not cast misdirection to make his lieutenant die for his cause, allowing the villain to be imprisoned and eventually escape?

Also you could just use the events of the Spellplague.Tyr killed Helm by mistake. Would a truly good god do that? Tyr died and got ressurected. Who says he actually wasn't "damaged"? Who says this cult is not following an imposter? I mean have you heard about a god being simply revived? Even in a world where you can bring people back from the dead, bringing a god back sounds a bit like you're lying.

Ah i'm not 100% sure helm is in our game as this is somewhat of a custom pantheon with gods from real mythology a bit of the faerun and greyhawk setting but more importantly religion's were subject to a purge I mean even knowing who vecna is like a DC 35 knowledge religion check basically classifying as an elder god. Also straight up having a moderate evil aura is a death sentence. I've only managed to skate by using a ring of undetectable alignment.

More so I'm trying to come with with hooks that would cause a mage hunter to fall from grace or find faults with his own place in Tyr's worldview that I can expand on. One to two sentence hooks. is basically all I'm looking for.

This character really adheres to a scholar mindset bonus points for anything going along with this!