When it comes to Leo and Leon they are twins but Leo is technically the older twin as he was born a little earlier than Leon was, as young children Leon was always more timid and shy almost beyond the point of cowardly. Often he would hide behind, cling, even go so far as to drag his brother off if he were afraid of startled. It did not help that their mother viewed him as the weak link due to this behavior and his lack of magical prowess Leo was always the stronger mage. As children, Leon was shorter than his brother for quite some time something that made sense at the time, but once he reached the age of 16 he grew taller than Leo reaching a height of 6′2 just one inch shorter than their elder brother Xander (Aaron’s).
Leon is a Dark Knight in class (Swordmaster) in other Au’s and verses whereas Leo is a Sorcerer (in most verses and canon), showing how Leo truly had more of a knack for magic where Leon had a better time using swords always carrying around his Ice blade (without the drawbacks in the game). We have so many au’s branching off twin verse it’s a little difficult to keep track of them all, (honestly most are angsty as all living hell lmao). Leo being the oldest always protects Leon in any given situation whether he likes it or not like an overprotective tiger, Leon would cling to Leo so often that the other could no longer go even an hour without the touch of someone mainly being his brother.
Leon can use tomeless magic but it always ends up hurting him immensely, even leads to a plausible death if overused causing his brother to become worried and scold him for using it but all in all Leon loves his big brother Leo more so than anyone else they grew up together. If at all avoided he would do everything he could to never upset Leo, he may tease him and joke around but there is always a concern he does nothing but annoy his dear big brother.