Help putting story into flaws

A Templar with Sense Holiness and Unholiness realized trough the 3. crusade that both side have holy people and so became disillusioned. In the end he deserted to the Byzantine Empire because of this.
What kind of flaws would you give this character from this story? I think the Dark Secret Major Story Flaw could be one way to put this story into a flaw but maybe some of you have a better or additional ideas.

This looks like the Templar (RoP:TD p.92 Brother Knight likely) broke his lifelong Vow (ArM5 p.60) of obedience.

This implies, that his Confidence Score drops by one - typically to 0 - until he atones in some way decided by the SG. It also removes all Faith points acquired so far.

Public religious penance would likely destroy his reputation among Western Christians. So yes, while he keeps his desertion a secret - in ways I cannot see - it forms a Dark Secret.

But I would use this desertion to rebuild the character completely, as his entire position in the world, social and spiritual, has been shattered: so don't be too mechanical about it, if you wish to keep that character - and perhaps its player - in the saga.

Cheers

I actual plan to use this story as pre saga background for my companion who at start of the story then have the Minor Social Custos + Minor General Educated Virtues.

Something that is similar, but slightly wrong, and could serve as the basis for a houseruled flaw is "Failed Monk"

I would stress that a Story flaw is not by itself a background story Flaw.
A Story Flaw is a way of saying "I want stuff to happen to the character revolving on this".

So, Dark Secret is appropriate if the character must keep his past hidden or face serious consequences, and a lot of stories make the past tend to resurface, so the character has to go out of his way to keep his cover. One example would be if the chararacter defected, and a few of his fellows know/suspect about it, and he's returned back to templar lands while trying to cover up what he did. But keep in mind, that by taking the Story Flaw you are telling the Storyguide that you want the dark secret to constantly be a source of trouble.

Alternatively, the character might be living happily in the Byzantine Empire, but is facing the undying enmity of the templars (or a few templars) who have sworn to bring him to justice, and he occasionally meets them causing him trouble in inopportune situations: perhaps he has to travel a lot to foreign lands where they hold sway, or they just keep sending an assassin after the other at him. This is the Enemy Story Flaw.

If the templars don't particularly care, or they have sworn the most terrible revenge but he's just out of their reach, he might be indebted with the Byzantine folks who took him in. If they now and then have a favour to ask in return, that's the Favours Story Flaw.

Of course, you don't have to limit yourself to Story Flaws. In my saga, a knight who had become disillusioned about his lords and turned outlaw, Robin Hood style, just had the Outlaw Social Status Flaw (and not the Knight Virtue). Because the knight had then taken up service with the covenant, and we did not want to have stories revolving around the lord chasing him, he did not take the Enemy Story Flaw.

Either way he likely has the foreigner flaw.
Plus the Byzaantine in 1220 is under Latin control, so it might not be a great place to hide...

thanks all, I decided to go now with a different story for the char. But the info about a foreigner flaw is really interesting as I didn't see such a flaw so far.

in Grogs "foreign upbringing" which may, depending on the situation, be combined with "outsider"