Hey welcome to this: thread of every Grey appearance from the sea temple arc UP UNTIL the reveal
And mayhaps youll see a trend here

finral - asta - magna

luck - gauche - then im assuming still gauche or Random Male

more of this guy

Alright now listen. Normally Grey will take on the personality and speech pattern of the person transformed into. HERE Grey is talking a lot, bein cheeky, actually making conversation which isnt really Gauche's thing
Then . the uwahs :/ BUT THAT'S NOT WHATS IMPORTANT HERE

Then here we go

BUT PLS NOTE LITERALLY NONE OF THEM KNOW WHAT GREY ACTUALLY LOOKS LIKE AND USES HE
Now let's assume Grey has been a black bull for at LEAST a couple years (2nd image from the elf invasion arc is Yami talkin abt Grey joinin and only 1of the panels shows tru form)

In the past x amt of time Grey has not shown trueform to any of the bulls (except Yami i suspect but have no evidence) & when not impersonating other people Grey is shown as such: A hulking goliath of a man

Now going back to the examples of Grey's transformations they are all:

Male. The only time Grey has transformed into a female was Charmy & that is AFTER the true form reveal before the the reveal? All males.

Now this
Grey has been using mana this whole time since being around the bulls as to hide true form, that kind of commitment is past being shy

Grey says "i'd rather die if i can't transform", Grey would rather die than to be seen in true form: a small woman.

Now look. I know its a longshot bc lets be real: trans rep in a SJ manga is doubtful (yes i know abt the rep in bnha but thats a whole nother can o worms)

But. There's signs that point to it so im not completely deranged not to mention trans ppl having trans hcs because they want to feel represented/have fun has no influence on your life. It costs $0 to respect trans people.

I am not SAYING THIS IS CANON im just saying this is how /I/ see it bc this character means a lot to me. You can see Grey however you want but I'm just saying i personally headcanon Grey as trans masc.

And thats it !