Batman has had a mixed legacy with sidekicks, raising Dick Grayson to become the heroic Nightwing, but failing Jason Todd, who reinvented himself as the lethal hero Red Hood. However, before Jason Todd returned to Gotham and began slaughtering its criminals, another killer sidekick sullied the Bat-Family's good name. This time, however, it was Dick Grayson's charge who attempted to become a lethal protector.
https://screenrant.com/nightwing-nite-wing-extreme-90s-superheroes-red-hood/