The Basics:

Full name: Tyrell Fitzroy von Nettesheim
Nickname/Alias: Ty; Fitz
Age: 13
Birthday: August 8, 1993
Sex: Male
Eyes: Pale blue
Hair: Dirty blonde/mouse brown
Height: 137cm (54 inches)
Weight: 32kg (70 pounds)

School Facts:

School: Cordell Academy
Year: Three
House: Keys
Favourite School Subject: History of Magic
Least Favourite Subject: Anything practical

Family Facts:

Pet: Lizard; named Papyrus
Father: Mason von Nettesheim (Muggle)
Mother: Cassia Della von Nettesheim (witch)
Brothers:
Tristand Keaton vN (29)
Harvey Jude vN (25)
Nigel Cary vN (22)
Steven vN (21)
Thomas Barry vN (19)
Henry Alfonz vN (19)
Zander Foster vN (17)
James Arley vN (15)
Benjamin Brant vN (10)
Johnathon Frans vN (10)
Robert Wood vN (5)
Jacob Alfred vN (3)
Sisters:
Marinda Hilda vN (27)
Käthe Kerrie vN (25)
Alicia Madonna vN (25)
Antonette Aletha vN (18)
Bianca Lan vN (14)
Dianna Neassa vN (12)
Trinity Gloria vN (12)
Julia Celadine vN (11)
Rochelle Anne vN (10)
Lynn Anselma vN (9)
Olivia Oriana vN (7)

Some of Tyrell's siblings are adopted, some are not. It's about a half and half split, and some of the same-aged children are not twins, while some are, and one is a set of triplets.
Tyrell himself was adopted at age five.

Assorted Facts:

Favourite Food: Spring rolls
Least Favourite Food: Sushi
Allergies: Bee and wasp stings
Favourite Colour: Yellow
Favourite Author: Shel Silverstein
Favourite Animal: Lizards of almost any description