In the DC Universe, superhero identities are often mantles for different characters. Character often change identities or 'graduate' into a new guise. For a long period of time, Dick Grayson was known to comic fans as Nightwing. Before that, he was Robin. He even spent some time as Batman.
Now, Dick's given up being Nightwing with the world believing he's dead. He's spending his time in the secret spy ageny, Spyral, and just goes by Grayson, or Agent 37. As much as we'd love for Dick to return to being Nightwing (and with a return to the blue costumed version as well), we're really enjoying watching the events unfold in GRAYSON. We say, let Dick be a spy for a while longer but the name and guise of Nightwing is too good to let go to waste. Perhaps it's time for someone else to graduate and become the new Nightwing.
Cassandra Cain
Cassandra Cain has a long history in the Batman Universe. Unfortunately, all of that has changed with the New 52. She will be returning to current continuity in the pages of BATMAN AND ROBIN ETERNAL. Previously she's gone through different identities as Batgirl and Black Bat. Batgirl is being used by Barbara Gordon and I never cared for the Black Bat name for her (plus that name belongs to another comic book character).
PROS: Back in 2011, we suggested Cassie become Nightwing when Dick was Batman. She has a strong following and is a highly skilled fighter. We're not sure what her return will mean for the character or where she'll be in her own timeline. She deserves a good name.
CONS: This could be a Cassie with less experience. We don't know how long she's been fighting. It'd be hard for her to graduate to the mantle without any prior connection to Batman. Unless, as last we saw her in the pre-New 52 universe, she's been working undercover for Bruce in Hong Kong.
Harper Row
What has Harper been up to lately? We saw her have a good sized role in BATMAN ETERNAL. When she first started appearing, especially after the death of Damian, it felt like she was being set up to become the next Robin.
PROS: She picked up the name Bluebird during BATMAN ETERNAL. It feels similar to Nightwing and would be close to the blue-suited version. Harper is a tough, no nonsense character. Bluebird doesn't really evoke a strong tough vibe. Then again, neither does Robin. Harper is already in the Bat-Family's good graces.
CONS: It seemed there was some resistance among certain fans when it appeared Harper was getting closer to Batman's inner circle. She has helped out Batman in some dire situations but still doesn't quite feel like she's done enough to fully earn the title.
Tim Drake
Tim Drake quickly became a fan favorite when he discovered Batman's true identity on his own at a young age. There may be the controversy of whether or not Tim actually spent time as "Robin" or simply has always been known as Red Robin but he's still the highly intelligent and skilled crimefighter. We're also seeing him in the 'future' as Batman Beyond. If he can take that identity, why not one more?
PROS: Tim Drake needs to be back in the Bat Universe. He's had some decent stories in the New 52 with the Teen Titans but it feels like something is missing with this version of the character. Some feel he should become Batman some day. Let's bump him up a little. He also might want to distance himself from the growing number of Robins with the We Are Robin team.
CONS: Tim as Nightwing would be cool but it's possible he might lose some of his own identity by taking on the role. Time has so much potential and his current role in the DCU needs to be straightened out before he tries taking on a new identity.
Duke Thomas
Duke Thomas is the kid seen during the Zero Year arc. He's currently appearing in WE ARE ROBIN (as one of the new street fighters) and is also up to something as seen in BATMAN #43 when he grabbed the seed from Mr. Bloom in Bruce Wayne's office at the community center. He wanted to fight the Riddler during Zero Year to save his family (and Gotham). You can feel that he's being groomed for something in the DCU.
PROS: Besides currently being in WE ARE ROBIN, he's also been seen in two possible futures in different guises. In BATMAN AND ROBIN: FUTURES END, he was Robin. In the weird future vision Bruce had in BATMAN #35, he was seen in a different costume with the name Lark.
Then again, Harper was also in that vision with a different Bluebird costume. Maybe she could still become Nightwing.
CONS: Duke is still pretty raw in the training department. He's showing some great tenacity in WE ARE ROBIN but he's barely a Robin right now. He should definitely get some more experience before becoming Nightwing be it does look like he's a really fast learner.
Carrie Kelley
Why the heck was Carrie Kelley introduced into the New 52 universe? She was brought in to seemingly throw off readers after Damian died. She was seen in a Robin suit at a costume party (even though it's been reestablished that none of the Robins wore the short short and pixie boots in the New 52 timeline). Maybe there's still something to her?
PROS: Actually, we can't really think of anything. She was good in THE DARK KNIGHT RETURNS but we can't just figure out why she's here.
CONS: She hasn't done anything to earn the right to be called Nightwing. There'd likely be a huge outcry if this came to be.
Someone Else?
Could we see a new character take on the role? We could joke further and suggest Bruce Wayne since he's not currently Batman. There's also Jason Todd since he literally stole Dick's guise (in NIGHTWING #118 through 122) but that didn't end well. Damian? Jim Gordon? This could also be the chance to create a new character that could take on the role.
It's possible we simply won't have a Nightwing for some time. Maybe Dick will return to the role after he's done with his spy stuff. We're not necessarily in a rush to see that story end.
Who do you think should become Nightwing? Should the name just be left alone until Dick is ready to return?