The Underground (or Under-Side) is the nickname created by residents of (some town) to describe the gang-activity/illegal activity that happens underground in the sketchy parts of town. The Undefined follows four main characters (and four supporting characters) whose lives become involved and entangled with the Underground and the Privileged. They ultimately have to make decisions that define who they are, but they also don't want to be bound to their past or appearances, hence being called Undefined.

The main characters:

Asiel (Ace). He is supposed to be middle eastern, a very skinny and of average height, Ace does not tend to stand out from the crowd. He is an oboe player in the school's concert band, and is a star mathematician on the school's math olympics team. He's very good with technology/science/math/logic stuff etc. He lives in a rather wealthy part of town and comes from a rich family. He dresses nicely, in collared shirts and sweaters very often.
Nishat (Nishi). A short (very short) black (brown?) girl. She is very loud and outgoing, and despite her stature, can put up quite a fight. She has ties to the Underground (for unknown reasons, friends, siblings?). Her outfit consisted of a baseball cap and a vest. She often had her hair up in a ponytail.
Zachary (Zach). Tall mysterious Asian dude. Has a lot of scars so he has a reputation for being tough and getting into fights and stuff. Wears mostly black, and has those biker gloves with no fingers.
Mikil (Micky). Stereotypically blonde, curvy white girl. People tend to label her as not very smart, though she really wants to join the math olympics team. She surfs and is the daughter of a very wealthy businessman. Attire consisted of a blue and white striped sundress, floppy hat, tote bag, flats, and a heart-charm necklace.

Minor Characters:

-Rei, a clarinetist in Ace's concert band. She's very quiet and proper, and has never dared to step out of the character she has been told to be. She's Japanese (I often remember sketches of her sitting at a kotatsu(???), shoulder-length schoolgirl hair, rarely smiles.
-Ivan, the deathly charming jazz musician. I never quite settled on a final appearance design for him. Either he was to be modelled like Flynt from RWBY or he would have a lighter complexion and resemble Ace a bit ("cooler" Ace).
-???, someone who is friends with Mikil. He's got longer surfer boy hair (blonde), bright blue eyes, and is very well built physically.
-??? who are you ???

I'll discuss backstories and relations next time.