Use this card in combination with "Unstable Evolution" while your Life Points are lower than your opponent's during the turn you Normal Summoned it in order to boost its ATK to 4800. After that, "Speed Warrior's" ATK will still be 2400, and when your Life Points are higher than your opponent's, its ATK will still be 1000, which is better than what it started out with.
Use "Megamorph" with the above combo to get 9600 ATK.
When you Normal Summon this card, you can activate its effect, then activate "Begone, Knave!" to bounce "Speed Warrior" after a direct attack so you can use its effect again.