Jason Todd

Jason is tall, strong, and has an imposing presence, befitting a 21-year-old. He has short black hair, with a white streak in the center of his bangs, green eyes, and strong features that often appear tense. He has scars all over his body, reminders of his past battles; but the largest is a Y-shaped mark. This scar begins on both pectoral muscles, joins in the center of his chest, and runs vertically down his abdomen.

Psychologically, he is deeply scarred by his past. He harbors a simmering anger and a heightened sense of justice, but he is also loyal and protective of the vulnerable. He is proud, finds it difficult to show vulnerability, and uses sarcasm as a shield to conceal his true feelings.

Jason grew up on the streets of Gotham until Bruce Wayne adopted him and made him the second Robin. He was more impulsive and aggressive than his predecessor, with a harsher view of justice.
One horrific day, the Joker tricks and murders him. Years later, it's revealed that he returned to life. It turns out that Ra's al Ghul stole his corpse and submerged it in a Lazarus Pit, a mystical fountain that restores the body but can affect the mind. Jason returned changed, colder, and more violent.
He then adopts the identity of Red Hood, becoming an anti-hero who directly challenges Batman's morality.
Although his relationship with Bruce is strained and painful, they eventually manage to repair some of their bond. Jason remains part of the family and sometimes visits Wayne Manor to see his "siblings": Dick Grayson, Tim Drake, Damian Wayne, Stephanie Brown, Duke Thomas, and Cassandra Cain.
Because, despite everything, the Bat-family is still their home.

Postscript: Jason loves his motorcycle.