He had to be number one. One of the most surprising and dramatic moments in comics history, Wonder Woman snapped Maxwell Lord's neck. It was one of the events that kicked off Infinite Crisis, one of DC interminable crossover continuity extrrrrrravaganzas. Originally the shady entrepreneur behind the formation of Justice League International, when the Gene Bomb went off in DC's Invasion! storyline, activating previously-dormant superhero genes in certain humans on Earth, Lord gained the powers of mind control. In the run up to Infinite Crisis, Lord is revealed as the mastermind of a huge plot to kill all superhumans. He shoots Ted Kord, the once beloved Blue Beetle, through the head and mind controls Superman to fight Batman and Wonder Woman. Realising that even if Lord was apprehended, Superman would remain under his control, Wonder Woman saves the day the only way she knows how. She breaks Lord's neck. Despite saving many many lives, Batman and Superman reject Diana for her actions, which is frankly a dick move. This was the first and only time in DC's official continuity that Wonder Woman had killed a human, one not in demon form. She felt she had to do it. Do you blame her?