The following article contains spoilers from Nigthwing #95, on sale now.
Nightwing's secret identity (Dick Grayson) was revealed to the villainous Blockbuster at the end of Nightwing #95 (by Tom Taylor, Bruno Redundo, Caio Filipe, Adriano Lucas, and Wes Abbott). This discovery will undoubtedly give Bludhaven's protector undue trouble, but there is a bigger question that now needs to be answered -- what will become of Blockbuster? When villains learn the identity of their enemies, their fates are suddenly less secure than one would want to believe.
This coincides with another question that's been lurking in the background all this time -- where is Heartless? Bludhaven's resident serial killer has been making moves in the shadows while Nightwing and Blockbuster have been going at each other. He has also made clear threats to Blockbuster and may take his rival's reckless behavior as an opportunity and reason to kill him. Ironically, this would make him Nightwing's last hope to preserve his secret.
Realistically, no matter how much Nightwing may want to keep his identity hidden, there are lines he won't cross to do so. Blockbuster may now know who he is now, but Grayson has always been determined to bring him down the right way. Ultimately, him knowing the truth changes nothing for the hero. Unfortunately, this also means that should Nightwing arrest Blockbuster, or even go after him at all now, his secret may become public knowledge.
This is where Heartless may come in. It's been odd that despite having such a large impact on Nightwing since he moved to the city and being the thing that motivated Nightwing to build the Haven, he has had remarkably little time in the spotlight since their first encounter. Blockbuster learning the truth might be the reason why.
When he first tried to form an alliance to kill Grayson with Blockbuster, he outright refused him. This prompted Heartless to quite savagely hurt Blockbuster by taking the one thing he cares about -- control over Bludhaven. This sudden rivalry was put on hold as Blockbuster resumed his attempts to get rid of Nightwing. But Heartless didn't go away, he's just been recovering, and in all likelihood will reappear before this war is over.
It's a perfect setup. Nightwing's secret has been exposed, giving Blockbuster an upper hand. Then, before he can make good on any threats, Heartless swoops in, taking advantage of his rival's lack of focus on anything that isn't Dick Grayson. In the process, Heartless would not only preserve his enemy's secret but also remove a major threat to the effectiveness of Bludhaven.
Ironically, a single act of murder would save not only the city, but Nightwing himself. It's a strange thought when the idea of a serial killer actually getting what he wants is exactly what Nightwing needs to continue being a hero. Of course, this is all just speculation, but the timing of it all coincides with Heartless' noted absence. It could potentially be paving the way to introduce him as Nightwing's next major enemy in a Bludhaven free of Blockbuster's corruption.