Okay so when there is talk of Nobody one thing is inevitable, comparisons with Batman's rogues will appear. Yes he's a character that is similar in style as the Red Hood and yes that doesn't make him an awesome Bat villain but the thing about Nobody is that I don't consider him as a Batman villain. When you look at it, a villain isn't just someone who poses a threat to the opponent sometimes a villain should be something that means something to the person he's fighting. And when although Nobody has history with Bruce Wayne and knows his secrets no matter how hard Nobody tries to convince the Bat we know Bruce is locked down on his beliefs, but not Damian.
Nobody from what I've seen seems like a character designed more for the growth of Damian as opposed to an enemy of the Bat. Damian is at the point where he wants to be respected for the way he is, we know Bruce has good intentions but Damian's a kid who just wants to be treated like an adult. It's hard for him that the person he idolizes (even though he doesn't show it) doesn't seem to trust him enough and it hurts him so at best Nobody could provide that trust Damian wants. It's not as if Damian doesn't have a reason to ponder an alliance with Nobody even if it won't be permanent, Nobody has shown Damian that he can trust him and by appearing in front of him a couple times without intention to harm him that he trusts him, Nobody is offering Damian not to be someone who he's not, but most important throughout the course of these books he's shown that the Batman isn't invincible. Nobody will represent a rift in Damian's consciousness the one that chooses between the good that The Batman does (be it through Dick or Bruce) and his upbringing. And it's not as if anyone else can fit Nobody's role, you put Jason Todd in and what's stopping Damian from treating him like Tim Drake and we all know there is no love lost between Damian and Ra's, I believe Nobody was created for this specific reason.
But as far as these things go I highly doubt it that Damian will betray Bruce at least not all the way but what I'm trying to say is that Nobody could very well represent what Joe Chill was to Batman in that what Nobody if written correctly could be part of Damian's history. I see Nobody as a character that would end up in comic book limbo but that doesn't mean he as a character cannot make a lasting impact on Damian. Through Nobody will we see a possible significant growth in Damian and his relationship with his father, through Nobody will we see a significant growth with Damian.
In closing Nobody may not be an original Batman villain, hell I don't consider him a Batman villain at all but I do consider him as Damian's "first" villain and what he represents to the dynamics of Batman and Robin is his strongest aspect.
*comes back to the realization that I'm relatively new to the DC universe*
*runs away and hides in fear of possibly having said something completely dumb/ignorant*