Sure, here's my two mains.
Pay no mind to the awful old sketch!
This is Julian, current guesstimated age is 26, height 5"1'. They were found in a sack by a creek at the age of 8, and spent the rest of their adolescences in an orphanage and various foster homes. Julian's real name, age, and origin, etc, are unknown. Coming to the orphanage with no identification, only knowing broken Russian (mostly profanity), and having no understanding of how anything works.
Julian is a passively suicidal melting pot if sickness, something is always wrong with them physically or mentally, which can make them a burden to others. Feeling the need to always be useful Julian is a workaholic with little development as a person, they never took the time to discover interests or hobbies, or gain a real sense of personhood. Also being a cynical pessimist who's stubbornly submissive, putting the lives of other's over their own, but will occasionally lash out due to over-stimulation or their poor health... or if they need a smoke. Sometimes having a complete meltdown.
This is Apollo Rivers, currently 26 years old, height 6"2'. Apollo was orphaned as a baby, instantly being adopted by a well off couple who wanted him for his unique eyes. After being paraded around in front of the press for a few months Apollo was dumped in a house with a nanny, hardly ever seeing his parents, and being left to his own devices. Finding Julian when playing at a small park with his nanny one morning, the two stuck together like glue till their late teens.
Apollo lives with a rare condition called ocular albinism which causes him to have eye problems such as extreme light sensitivity, bad depth perception, and nearsightedness. This condition has caused Apollo's irises to give a purple look under normal conditions, due to the pigment being iridescent enough for the blood vessels to show through. (If you were to shine a light in his eyes they'd show red) Being a kid who grew up in a sheltered environment, doing whatever he wanted Apollo became a party enthusiastic, alcoholic. He is an overly trusting, mostly apathetic, self-centered, dumb-dumb who's a little too excitable.
Apollo is an alcoholic due to a combination of loving to party, peer pressure, and a smidgen of guilt from something that happened between him and Julian when they were teens.