Alright, before putting out a CS, I need to ask something. If I pick a character, do I have to use their official canon personality?

I mean, I was thinking of using Bjorn the Fell-Handed from Warhammer 40k, only using his 1d4chan personality... By which I mean, I mean to play him in his only incarnation that gives him a unique and interesting personality. See, 40k has this weird notion that giving a character a laundry list of cool shit they have done in the past, and giving them a personality are the same thing... They are not. GW Bjorn is a generic "I am a big angry space marine, EMPRAH AND WOLVES FOREVER!!!" character like every single other Space Wolves character, but 1d4c gave him actual personality traits, such as his dislike of Russ for being a jerk that gave him the name "The Fell-Handed" after finding him masturbating behind a boulder and ratting him out to everyone. Or how he absolutely hates the Iron Priests because they keep overloading his body with more Wolf iconography when he's asleep. Or how he despises Logan Grimnar, because the old fart only wakes him up ever other century, in order to tell the kids stories of how great Russ was. And how he wishes more than anything that he can go back to war.

Would I be allowed to do this? 2 other plays have already told me "Canon personality or nothing!" Please have mercy on my fun idea T.T