Kid Giant is a major antagonist encountered in "Fairytale Fights" and was the one responsible for kidnapping numerous princesses, once of which the player-controlled hero was trying to rescue as part of an ongoing quest.
Kid Giant attacked the hero with his sheer size, smashing a fist through a tower roof and continually trying to snatch the hero while also occassionally blowing gale-force wind from his mouth. He was only vulnerable when he paused to peer into the hole, at which point the hero hit at the giant's eyes. However after being defeated, Kid Giant flies into a truly monstrous rage and lays waste to the tower, burying the hero in debris before kidnapping the princess regardless.
Kid Giant then proceeds to take the princess to the Giant Kingdom on the top of the beanstalk - prompting the start of a new chapter in the game. When the hero pursues him into the clouds they manage to hitch a ride via grabbing onto the long hair of one of the princesses (presumably Rapunzel). The hero then fights their way across Kid Giant's room in order to confront the giant once again.
In the second battle, Kid Giant shows his destructive side as he attacks the hero with an assortment of gruesome "toys" - including a catapult that literally flings princesses at the hero, one of the more dangerous "toys" is a small dragon that he uses like a flamethrower.
After a while he also reaches over to snatch the hero, which is when he is vulnerable to attack once more: he is also vulnerable to attack when he peers at the hero during the induced fights with his "toy" soldiers (once again, his eye being the weak-point). After his second defeat, a bruised Kid Giant throws a temper tantrum and is hit over the head by his disgruntled father: allowing the hero and princesses to escape in the distraction, which makes Kid Giant break down into tears like a spoiled child would do.