My gosh this is wonderful I love how you did Nightwing. I so confused on how many sidekicks Batman had gone through not just the robins. So we got Dick Grayson, Jason Todd, Tim Drake, Damian Wayne, Carrie Kelly, Stephanie Brown, and Barbera Gorden.... I wanna through Terry in there but he was more of a apprentice. It's like each day I search for a comic a new Robin pops up.
I would say Terry was Bruce's replacment as far as the Beyond story goes... cant say he was a side-kick. Terry and Bruce team-up similar to how Babs "Oracle" teamed up with her other Batgirls, Cassandra and Steph.
That being said... I couldn't consider Babs a "side-kick" of Batman. She was there but she was kinda her own thing. More like "co-workers" then an "underling" as Robin is consistently.
I feel Robin is more Batman's side-kick while other characters like Nightwing, Batgirl, Bat-Woman, Batwing, Red Robin and so on are more their own beings are characters who are not under the shadow-of-the-bat.
Just one question, why didn't you include Stephanie also? She was also a Robin, so was there a reason or do you just not like her as a Robin? Great work by the way, I really like the poses especially Carrie's