Robin:
Villains: Mysterious crime boss, Deathstroke the Terminator, street thugs(minor)
Plot-Robin travels to Bludhaven in search of his own hero career after Bruce had him leave. Robin chose Bludhaven because it is a crime-ridden city. After making a name for him-self by randomly kicking ass in the streets, the city starts to see him as a hero. A crime boss gets word of a Robin guy going around town and beating up his thugs, so he hires assassin Slade Wilson A.K.A Death-stroke to take him out. Death stroke is constantly on Robin’s tail, attacking him whenever he can. The final battle at the end of the movie would be in a factory with Robin looking for Deathstroke throughout the building. He eventually comes across Deathstroke and fights him, leaving him for dead in the factory.
Post-Credits Scene: Deathstroke is shown getting up and forcing his way back to the crime boss’s office. He demands he be payed. The crime boss tells him no, so he disappears behind him and slits his throat. Slade Wilson collects his pay, and vows he will kill Robin for making a fool of him.
Robin 2:
Villains: Deathstroke, The Death-stroke gang
Deathstroke is now in control of the Bludhaven Mob. He is having them hunt down Robin and to draw him out, they start murdering innocent people. Robin starts beating the deathstroke gang throughout the film but more and more keep coming. He himself organizes a one-man raid on the Mob hideout. He goes through the mob hideout and beats the crap out of Death-stroke gang members. The film ends with a battle between Death-stroke and Robin in Deathstroke’s office. Deathstroke almost kills Robin but Robin comes back and starts beating Death-stroke to death. He lets Slade Wilson live after a realization, but he sends him to prison. Robin decides to retire the Robin get-up at the end of the film and he becomes Nightwing.
Post-credits scene: Deathstroke has been broken out of prison by a mysterious benefactor, who only left him a file called “Project H.I.V.E.”
Robin 3: Nightwing
Villains: Deathstroke, H.I.V.E.
Now in the story, Deathstroke is recruiting members for H.I.V.E. He comes across a group of people with incredible talents and a dark side to them. Of them are Jinx, a female master of illusions and trickery, Gizmo, a computer hacker and technology expert, Mammoth, a bodybuilder with incredible strength, and Gorilla Grodd, a man with a body-condition that gives him the appearance and natural abilities of a gorilla. Death-stroke under orders from H.I.V.E. and it’s mysterious leader, has sent them to fight Nightwing. Nightwing throughout the film battles them at various locales throughout Bludhaven. He defeats Jinx by using illusions against her, Gizmo by hacking his network system for his robots and turning them against him, Mammoth through a fists-and-feet brawl, and Gorilla Grodd by fighting him on a construction site using acrobatics and weapons. The film ends with Nightwing and Death-stroke facing each other again, each vowing this will be their last duel with each other. They fight and fight until eventually both of them are exhausted. Nightwing gets up now with the fury of the Hulk and slaughters Deathstroke to pieces. Eventually, Nightwing realizes he has killed someone again, sheds a tear, and vows to never kill a villain again.
Post-credits Scene: Robin is shown watching a news segment on Super-powered beings and sees 4 that he is interested in. He decides to jot down some plans for a super-hero team. Meanwhile, The H.I.V.E. leader is revealed to be a woman, and she is shown training the villains who appeared previously in the film, reveling they’re still alive. Also seen is an army of H.I.V.E. soldiers.
Yeah, the first spinoffs are the Robin films, which eventually turn into the teen titan films at the end of Robin 3.
Also, Robin's costume is a long trench-coat in dark red with a yellow R on the back. The Nightwing costume is a black trench-coat with Blue stripes and a black-and-blue shirt with black pants.
Deathstroke would have his costume from the comics.