Grudge Match

When Huntress follows Black Canary into the city of Bludhaven, there's a cameo by Nightwing in the shadows perched atop of a building among gargoyles as he overlooks the bridge to enter the city. This confirms what Commissioner Barbara Gordon mentioned before the flashback scene in Batman Beyond: Return of the Joker (2000), that Nigthwing/Dick Grayson left Gotham City to establish himself in another city. Just like Nightwing does in the post-Zero Hour comics, he establishes himself as the hero of the city of Bludhaven.

References Batman: Mask of the Phantasm (1993)