The entire stage consists of four item statues before you go straight into the boss fight. The boss is the legendary demon Jagu, to whom Flare has been choosen to be sacrificed. He doesn't so much appear as he materializes after the spirits of other defeated enemies assemble. Once he blinks into reality, the fight begins.
Jagu is quite large, but he has no form of attack other than stomping on you as he jumps around the screen. He leaps into the air and lands in another place, remaining there for a period of time before jumping again and landing somewhere else. When he does jump, he propels himself off the ground with his back leg (i.e. if he jumps to the left, he will push off with the leg on the right.) The leg that he pushes off with will remain lower as he jumps, increasing the likelihood that it will hit you as he jumps through the air. If he does hit you, you will lose three bars of health, meaning you can only sustain four hits at most before you die.
If it does appear that Jagu will land on you, squat down. You will not get hurt if you do not stand up. However, remaining in this position will leave you vulnerable to getting hit by that kick-off leg if you're closer to the wrong leg. However, while you are down there, you can strike him as much as you want. If he is standing on the far right or far left, try to lure him into the middle to avoid having to squat beneath him until you have no other choice.
Naturally, you should try to hit him with full 100% strength strikes. If you only hit him with full strength strikes, you can defeat him with 8 hits. As he takes more damage, the glowing stripes on his body change colors, from shades of blue at full health, to yellows and greens, and then to reds and purples when he has less than half of his total health. Once he is defeated, you will be rewarded with the game ending and the programming credits.