#so sorry...

brand locations + brand appearances

i will say that, as far as i can tell, the idea of psykers being branded began after dark heresy 1st edition, the tabletop rpg, was published and all imperial psykers in that game begin with an item called "Sanctioning Brand." we have to go with the basis that 40k was originally meant as a role-playing game, so you can take away or add things to lore as you like.

i really like the idea of a psyker having a brand, as it is another form of otherness that sets them apart from others. psyker gear is even specifically designed to make them stand apart from others, as per a darktide item description:

Much of a psyker's wargear is designed to remind of their otherness. After all, one can never entirely trust them.

fun part, we actually don't know explicitly what the symbol mentioned in dark heresy is. it's often called a "symbol"/"brand" because many, many, many imperial citizens are not fully educated + the vast range of low gothic (heinrix even swears in game in a form of low gothic you don't recognize) and its different cants, so a symbol would be easier to understand. idira specifically calls sanctioning a "seal" (very likely not literal, but...) on your forehead:

"Look… Lady Theodora couldn't care less if some eggheads measured my brains or not. It's not about the seal on your forehead, get it? It's about what's in your gut — if it's rotten or not."

i specifically selected the aquila for that heinrix post because, well, it was the only available tattoo that seemed similar to a brand. mostly commonly, sanctioned psykers are depicted wearing the symbol of the adeptus astra telepathica on their clothes, which i've included below:

normally, it would probably just be a brooch or a pin attached to them so that you could look at the guy lighting himself on fire without matches or gasoline and go, oh... a sanctioned psyker... that's a little better... i also used electoo in the post because another inquisitor, amberley vail from the ciaphas cain novels, has an electoo she flashes which identifies her as an inquisitor. so heinrix could also have something along those lines!

but, i also like the idea of it being a tattoo/a brand, as it helps re-enforce the idea of a psykers body not being their own. adds to the inhumanization and how psykers are almost treated like "cattle" (tbf everyone in the imperium is), and in our world, cattle and horses are branded. you can also say that if it was a brand, heinrix could have theoretically healed his with his biomancy + simply had the branded skin removed by someone (xavier?) and was forced to re-grow it.

as for location, i placed it on his back in game since the idea of it being on his forehead is so not stealthy, but i also mentioned wrists since the idea of heinrix having to pull off his shirt all the time to show the brand is sexy a little silly. alternatively, i saw some people in the tags talk about how they liked the idea of it being on the wrist since xavier could pull some power-play and shove up heinrixs sleeve to remind him [heinrix] of his place if it's ever needed.

as for the womb joke in the tags, um... i just really like heinrix... and those kinds of tattoos are pretty hot... i gave one to my rt even lol

anything below this is just some rambling about the sanctioning process.

the sanctioning process

so basically when a psyker is finally delivered to adeptus astra telepathica organization from the black ship, they are sent to scholastia psykana (psykana is a term also used to refer to "combat psykana" so the literal name of the school is education psyker or psyker education) for training. usually, this training happens very young, and is preferred by the school because children are easier to indoctrinate, coupled with previous hopefully imperium doctrination, and easier to train.

note that only psykers of a sufficient power, and in a specific age range, level are actually saved, even if they are picked up by the black ship. sometimes, even if you survive the journey to the scholastia, you will be rejected due to being too weak to serve as a combat unit (psychically) or simply too old, and will be added to the tithe of the 1,000 psykers that are sacrificed to emperor/golden throne (same thing at this point) every day.

for the sanctioning process itself, they have actually kept what happens pretty hush-hush. we know from a darktide twitch drop description:

Those who graduate from the Scholastica Psykana tend to look out for each other, for only they know the price paid.

that there is a sense of camaraderie with sanctioned psykers, (some of them even refer to each other as siblings, as they all share the same curse) as they are the ones that survived the "trials and rituals" of sanctioning, which heinrix mentions

"Mistress Tlass… You could still undergo the trials and rituals of sanctioning. Perhaps later I could help prepare you and arrange the process, if you will allow me."

the sanctioning process is meant to strengthen ones mind, a true final test that protects the psyker and ensures that they are able to shield themselves from the horrors/possessions of the warp:

"The situation on Footfall, with the Lord Inquisitor's guard… What possessed me? Could the sanctioning… be starting to fail? If that's it, then I don't have much time left… No, that's ridiculous!"

i can't find an exact description for what exactly a sanctioning ritual is, but my personal headcanon is that it is similiar to the harrowing process that circle mages go through in the dragon age universe (ie, they open your soul up into the warp and allow a daemon to be attracted to it, which you then have to defeat/shield yourself from to survive) we can also see some of the effects that happen after sanctioning (from the dark heresy ttrpg)