R = Robin (Jason Todd, DCU)
U-Uchiha Sasuke (i hate that guy >_<)
eh?
how could you miss R, S and T!?
N = Nightwing (adult form of Robin from the cartoon Teen Titans; appeared in episode 14: How Long is Forever?)
"adult" I hated that episode. They couldn't think of anything original so they stole Robin I's adult self when Teen Titans features Robin III, The writers for that show are stupid.