Heretical Crusaders

In what situation would crusaders, witch burners, and inquisitors would be heretics?

It would be a point of view thing. Another group could consider them heretics if they think the church they serve is corrupted / heretical.

In the situation when witch burners are Protestants

>Pope says: "Yo, be cool dudes, stop inquisiting and burning witches and crusading shit."
>They say no and elect their own pope
>Both popes excommunicate each other
>Now everyone is heretics
Repeat as necessary for the desired number of simultaneous popes. IIRC, real life got up to five once.

If witches are in charge, then witch burners are heretics.

If another faction wins control of the church, the losing faction are excommunicated as heretics. See Catholic/Protestant, Ireland, Mormons, etc.

Similarly, one faction might consider another too violent/soft, and cause strife.

Realize that some Christian churches have deep conflict over whether Christ was crucified with three nails or four, and dispute the matter bitterly. Then realize that when you're powerful, anyone who disagrees with you is a heretic; just pick your favorite opinion.

Honestly this. IRL heresy accusations were functionally no different than rules lawyering and edition wars skub arguments.

In real history, a heretic isn't someone who does sacrilegious things, it's someone who practices Christian doctrines contrary to your own. So, an Eastern Orthodox crusader would be a heretic to Roman Catholics, and a Coptic witch burner would be a heretic to Nestorians, etc.

Probably take inspiration from the fantasy version of the knight Templars who secretly worshipped the Mohammedan false god of Baphomet.

Also, see Warhammer 40K inquisitor radicals who use evil magics as a means to fight evil magic.

The Witch Burners are heretics because church doctrine tells us there's no such thing as witchcraft.

Isn't it heterodoxy?

No there were no Crusades against Christians (IV crusade was a Venetian conspiracy, so it doesnt count). Only ones that may count are against Cathars and Bogomils, but they were more Gnostic than Christian, so it doesnt count much.
This type of war that you state would be a more of a excommunication war as in CK2

Yes it is and user mistook it. Orthodox and Catholics at least, view eachother as heterodoxes, but not outright heretics.

You're correct, I was wrong. Heresy is a view which is much more fundamental than heterodoxy. Less like "It's fine to venerate and pray to icons" and more like "Christ and the Father aren't the same person"

>someone isn't Christian because I say so
This is exactly what heresy is you dummy, Cathars absolutely were Christian

No. Just to base your beliefs on SOME books that you share with the religion and to have something similar with said religion, doesnt mean that it is a same religion. Just because Islam recognizes Torah and Gospel, doesnt make it Christian or Jewish. Just because Mormons recognize Jesus as God (alongside numerous gods born by endless celestial sex) doesnt make them Christians.
Cathars were by heart Gnostic, not Christian

The first third, if not more, of the Malleus Maleficarum is a theological debate piece aiming to show that belief in witches isn't heretical despite the Devil empowering people to do bad seems to fit poorly with an all-knowing, all-powerful God not approving of it all. Much of the excesses of the Spanish Inquisition was only allowed to pass by through significant political pressure put on the pope by the Spanish crown. The fourth crusade got sidetracked into storming (orthodox Christian) Constantinople at the behest of a Byzantine prince with imperial ambitions, instead of their intended goal of going to Jerusalem.

The French king owed them a fuckload of money. The catholic church wanted to reduce the number of militant orders, the militant orders don't want any of that. And all of sudden the templar leadership is accused of witchcraft while the rank-and-file troopers are folded into the other orders. One less militant order for the church, all debt wiped away for the crown, and I'm sure those charges of witchcraft were well founded and true, yes sir.

The difference is mostly "Do I want to go to war with these guys?"

>we're the real Christians because our authority figure says so

I feel like you are quite severely ignoring the main argument

>The French king owed them a fuckload of money.
Philippe le Bel. This same king also expelled the Jews because he owed THEM a lot of money too. That's also the same Philippe who declared war on the Flemish due to some entirely made-up conflict that resulted in the Flemish paying a significant sum of money for their independence.

It looks like everything that king did was centered around filling his coffers. The Templars were no exception.

The Fourth Crusade.

Well, witch burners were heretics according to Catholic doctrine.

The crusaders that attacked Constaninople were already excommunicated by that point for attacking the catholic city of Zara btw

If a crusade is called by a schismatic or otherwise invalid pontiff, it is invalid.

Perhaps he maintained public order and stability by a system of bribery and patronage, and so always needed a lot of money.