Batmetal backing band

 I know the youtube channel behind Batmetal (and Batmetal returns) released their Batman themed viral-parody sensation well over a year ago now, but funny story- when Metallica's video for 'Hardwired' hit youtube I watched it to which youtube recommends a Metallica reacts video- which I also watched. On that video there was a recommendation for a Batmetal reacts video which reminded me again of Batmetal. Anyway, partly because I didn't completely know all about the different Robins and based on some of the comments not realising the song is not original etc I figure someone, even if it's just me, might take something away from a rundown on the characters making up Batmetal. Please bear in mind I'm not a comic book guy, this is all based on the characters appearances in DC / Warner Bros animated movies (TV series takes too long to binge through).

Batman- Vocals.
Everyone knows Batman, right? In terms of animates portrayals I'm a sucker for the big names- I'm quite a fan of Kevin Conroy (especially opposite Mark Hamil's Joker) Kevin Conroy voices Batman in "The Killing Joke"

Nightwing- Guitar. This is Dick Grayson's follow on from Robin. As the original Bat side kick, Nightwing has made appearances in pretty much all the animated movies which feature the other Robins'- certainly Red Hood as well as try-to-be babysitter for Damian Waynes in the some of his movies but I'm not sure he has his own Nightwing origin movie. Having said that, the way he is portrayed in movies like Bad Blood- where he takes over as Batman, Under the Red Hood, and others gives us enough to infer that he probably grew tired of towing the line with Batman as he grew up with their split being serious  enough to see him move away but not so bad as to abandon the Bat family entirely.
Nightwing sparring with a young Damian Wayne as Robin:

Dick Grayson's Robin accompanies Batman in a 2016 new animated movie based on the campy 60's Adam West version, which, having seen only the trailer of, I'm not sure how I feel about it...

Red Hood- Guitar Jason Todd's transition from Robin to Red Hood, as portrayed in Under the Red Hood, is more brutal and gritty- certainly more comic book like than a live action movie would i.e. Lazarus pits, Black Mask etc. Anyway, he, let's say- takes issue with Joker and Batman, or rather how Batman deals with the Joker.

Red Robin- solo. Tim Drake as Robin pops up in one of the animated release somewhere but I'm pretty sure that the character of Red Robin has not yet seen animated movie screen time.

Robin- drum. If you check out 'The Dark Knight Returns' pt1 & pt2 (i.e. animated movie) old man Batman comes out of retirement which quickly attrachs a new Robin. This time around the young, female Robin is less accomplished fighter so acts more as an assistant behind the scenes.Given the gender and appearance (i.e. glasses) of this Robin, through the process of elimination the only choice for drummer in this case is Damian Waynes. The son of Bruce Wayne is introduced into the animated movie universe via Son of Batman, and makes follow up appearances in Batman: Bad Blood, Batman vs Robin and the Justice League vs Teen Titans.
 Nightwing drives Robin (Damian Waynes) to Teen Titans