Cupid was based on the Greek god Eros who had 2 types of arrows. A poisonous one, and one that makes you fall in love. Eros would shoot one person with the poison, and another with the love arrow to make them suffer as the person they love slowly dies.
The first god could have just walked backwards while throwing the spears and the army would have been tripping over the corpses and spears so this wasn't even as realistic as it could be
