Curt Connors was never that intentionally homicidal. While the Lizard may want to transform all of New York City into carbon-copies of His Lizardness, Dr. Roderick Kingsley was first seen as the Hobgoblin in Peter Parker, The Spectacular Spider-Man #43, June 1980.
In the end, there was little more than the two killings to prevent his identity from getting out – not even a true homicidal maniac.
After becoming a costumed villain, he manipulates a small-time thug to fight Spider-Man, and then kills the thug after his defeat by the web-slinger, to prevent the thug from giving away the Hobgoblin’s true identity. However, one of Kingsley’s first acts, before actually becoming the Hobgoblin, is killing the man who tells him where the Green Goblin’s lair is. Kingsley becomes the Hobgoblin to further his own gains in the corporate world, strictly for financial power. Jimmy Natale was introduced as the new Vulture in The Amazing Spider-Man #593, June 2009. While he certainly isn’t in the villain biz for wealth or power, he qualifies as a villain unlike say, the Punisher, because he isn’t killing criminals and mobsters out of some higher moral standard. And, apparently, he has a taste for evil-doers with no remorse for killing.
Unlike Adrian Toomes, probably the most famous of the Vultures, Natale doesn’t need a suit to fly since he has mutated wings, a beak, and can spit acid. Jimmy Natale is a one-time mob enforcer that was mutated into a criminal-eating vigilante known as the Vulture.