King Croacus was the title bestowed onto the ruler of the Floro Kingdom, the exception being Queen Croacus II because she was a woman instead of a man. King Croacus IV is actually the only leader actually seen in-game, being the Chapter 5-4 boss. There is a palace in the Floro Caverns with pictures on all four leaders. There are signs underneath each picture that says the time that they he/she ruled, what accomplishes he/she made to the Floro Kingdom and how he/she died.
King Croacus IV is the only ruler that is not part of the royal family. King Croacus IV was originally the regent under King Croacus III. King Croacus III became the ruler at one year of age, and was a very sickly child at that. So, King Croacus IV (not a king yet) did most of the work for the third ruler. At age 88, King Croacus III died, possibly due to him being so sick, but some thought it was a conspiracy. This means that it is possible that King Croacus IV killed him in order to get the crown, but he was not evil at that point, so it is not likely.
King Croacus IV was a magnificent ruler according to his Floro Sapiens servants. He had experience as the regent under King Croacus III, so he could handle the job. Unfortunately, the near-by Cragnon race started to pollute the water. The Cragnons (except for the “Green Cragnon Crowd”) thought that they should return the garbage to the Earth by throwing it into their waters. But, this water was the food source of the Floro Sapiens. By only being able to drink the polluted water, King Croacus IV became insane.
King Croacus IV started a war on the Cragnons as revenge for polluting their water. King Croacus invented the Floro Sprout, which could brainwash the person it was planted into. The Floro Sapiens would capture Cragnons from the Land of Crag, bring them to the Floro Caverns and plant Floro Sprouts into them, making them Floro Cragniens. These mindless servants would serve the Floro Kingdom as slaves, usually digging for gems which King Croacus IV loves so much.
By the time that the Heroes of Light appear on Mount Crag, the Cragnons tell them that the Floro Sapiens are capturing them. The heroes send out to destroy the Floro Sapiens, following a group of them down to the Floro Caverns. At the end of Chapter Five, after obtaining a dead Floro Sprout from a defeated O'Cabbage, they are able to find King Croacus IV. King Croacus knows of what harm the heroes have done to his Floro Kingdom and he also has obtained the sixth Pure Heart. Over the rule of their kingdom and the Pure Heart, they fight.
The first part of fighting King Croacus IV is fighting his three smaller heads. Mario can jump on them to paralyze them, and then use Thoreau to throw them at King Croacus IV’s actual head. After that, King Croacus’ head detached from his body and spins around like a shuriken. His head is protected by the rose petals, making it impossible to hurt him. Two other smaller shuriken-like rose petals swing around. When his head is uncovered, the Heroes can hurt him or throw one of the smaller shuriken petals at him.
The Heroes of Light defeat King Croacus IV after a long fight, who temporarily wilts. The Floro Sapiens explain to Mario about what the Cragnons’ pollution had done to his health. Flint Cragley and his crew overhear their conversation, and Flint promises to tell the Cragnons to stop polluting the water. The Cragnons and the Floro Sapiens make a truce and live together again as allies. As thanks to the heroes for their assistance in them making peace, they receive the sixth Pure Heart. King Croacus IV survives and has now become sane, probably ruling the Floro Kingdom in a civilized manner again.