Hope youre doing well!! Do you have any Gus head cannons???
Random ones:
He often has to mediate sibling arguments between Cashmere and Gloss and, to new Victors, acts like a sort of 'decoder' for them to figure out real fights vs joking ones (bc they're remarkably similar).
The Capitol sees him as Gloss/Cashmere's younger sibling but they really aren't that close. They're close af, mind you, but neither sibling feels able to think of him as anything other than their Mentee, especially since they lost their own sister in the Games a year or two (depending on the AU) before his win.
He's an only child of an ailing single dad and enrolled in the Career Academy to help lessen the burden of his father's medical expenses.
He likes to pull pranks (often with Finnick who's the closest thing he has to a brother).
The only person he's never pranked is Penny (Penthesilia Escher, D2 Victor) (his love).
He's scary good at reading body language but, interestingly, chooses to care about what he 'reads' with certain people he loves and/or respects.
Gemaline had a huge crush on him for the first few months after her Victory. It has since gone away but it was awkward to say the least.
Thank you for the ask!