Generally accepted as the main protagonist of the Streets of Rage series, Axel Stone presents a strong balance of power and speed. While Axel only has a small array of moves in the original Streets of Rage, Streets of Rage 2 gives him a much wider arsenal of attacks, including his trademark 'Ground Upper' uppercut, one of the most powerful moves in the game. Besides this, Axel has two power moves: Dragon Wing and Dragon Smash, a circling strike and a leaping uppercut respectively, although neither are as widely useful as the Ground Upper.
In Streets of Rage 3, very little has changed in Axel's move set. Besides renaming his trademark uppercut from 'Ground Upper' to 'Bare Knuckle', the name of the franchise in Japan, the only real addition are his Blitz Moves which are simply quicker and slightly more powerful versions of his uppercut and the special Dragon moves.
Axel returns in Streets of Rage 4, having retired from the police force only to be called back to fighting due to the rise of the Y Syndicate. In Streets of Rage 4, Axel features a number of new moves, such as Dragon Burst, although a number of his previous moves, including Ground Upper, return. As well, Axel's previous incarnations (including their move-sets) appear in the game's DLC.
Although Axel's uppercut move is almost universally referred to as "Grand Upper", series' composer/sound effect designer Yuzo Koshiro has stated via Twitter that the move is intended to be "Ground Upper". Part of the confusion may have arisen from Streets of Rage 2's English manual, which refers to the move as "Grand Uppercut".