He was an aerodynamics engineer who showed his plan to OsCorp for Norman Osborn but was turned down until four months later, is embezzled of his work. This caused him to turn to supervillainy as Vulture to take revenge on Norman or Spider-Man.
It is unknown what Adrian Toomes was like at the beginning when he showed his technology to OsCorp but four months later, after learning that his work was embezzled by OsCorp, he became an angry and bitter man who turned to villainy to take revenge before becoming a minion of Doctor Octopus.
Originally, Adrian Toomes was an inventor, who created an anti-magnetic harness which enabled him to fly at high speeds and make agile aerial maneuver and showed it inventions to Norman Osborn. Osborn rejected it. Four months later, OsCorp announced Techflight 2.0, angering Toomes, who immediately recognized it as a rip-off of his work. He at first blamed Dr. Otto Octavius before blaming Osborn. When Norman refused to apologize, Adrian donned his Vulture suit and attacked. Eventually he was defeated by Spider-Man.
Later he helped in the prison break of all the villains Spider-Man had put away, then joined the newly created Sinister Six.
The Six preceded to fight Spider-Man. After Spidey was forced to retreat, Vulture was seen having dinner with the rest of the group. By the end of their meal, they had agreed Spider-Man had to be gotten rid of (though Vulture still wanted his revenge against Norman). In the rematch, he was defeated when the symbiote-controlled Spider-Man tore off the top part of his helmet, causing him to pass out.
During the Master Planner arc, he was somehow broken out of prison.
With the new six-now minus Doc Ock and Shocker and gained Mysterio and Kraven the Hunter, they attempted to fight Spider-Man again. Vulture gets teamed up with Electro during the fight. However, he is once again beaten, getting webbed to a Christmas tree, then electrocuted by Electro despite his warnings.
Vulture later accompanied Doctor Octopus to a bid, and then a meeting between him, Silvermane and Tombstone. Hammerhead betrays everyone during the meeting, causing Vulture to jump to the doctor's protection, only to immediately be shot by Hammerhead. He was last seen escaping with Silver Sable.
Adrian Toomes: I blame you for this! You told me to bring my magnetic-air transport system to OsCorp! Dr. Otto Octavius: I know. Adrian Toomes: You arranged the meeting with Norman Osborn! Dr. Otto Octavius: (stuttering while walking backwards down the stairs) I had the best intentions. Adrian Toomes: He studied my ideas and rejected them and then announces OsCorp flight tech four months later! Dr. Otto Octavius: I... I am sorry Adrian... Norman Osborn: Don't you dare apologize, doctor. OsCorp has nothing to apologize for. Adrian Toomes: (angrily stunned) Nothing to a... Osborn! You stole my work! Norman Osborn: (smugly) That's dangerous talk, Mr. Toomes. Dangerous and unsupportable. Listen you old buzzard, you've been at this for decades without one success to your name. If you never accomplished anything as a young man, who'd believe you created tech flight as an old one? (to his body guards) Boys? show Mr. Toomes out. Adrian Toomes: (to Dr. Octavius while being escorted out) Good news! I don't blame you anymore.
~ Adrian Toomes confronting Norman Osborn and Dr. Otto Octavius for embezzling him of his flight tech.
~ Vulture kidnapping Norman for revenge.
Vulture: Tell the truth, Osborn! Can your tech flight do this?! (flies acrobaticly) Norman Osborn: Toomes?! Vulture: Not Toomes now, I'm what you called me! I'm the Vulture! Norman Osborn: I called you a buzzard! Vulture: What? Norman Osborn: You can't even get the name right! (gets thrown by Vulture before getting caught by him again) Toomes, stop! What will any of this accomplish!? Vulture: A means to an end, Osborn! Something you know all about! You will announce to the world that Adrian Toomes is the genius behind tech flight! You will pay me all that I'm owed and you will publicly apologize for stealing my invention! Norman Osborn: I never apologize, old man! Vulture: I may be an old man, but I'm not a patient one!
~ Vulture threatening Norman to tell the truth to the world about him being the genius behind the flight tech.