Evil Crystal
The Evil Crystals are items in Densetsu no Starfy 3 which are only obtainable after defeating altered Ogura for the first time. They are round, red crystals used together to truly defeat Evil. While 40 of them are found at the end of past levels, one of them is given by the Pufftop Scholar, while Ogura holds the last one as a source of power.
Starfy, Starly and Moe seek advice from the Pufftop Scholar on how to stop Evil, who then answers in a lecture that all 42 Evil Crystals must be gathered, as defeating Evil without the crystals will not help. When Starfy, Starly and Moe return to Old Castle with 41 Evil Crystals, they realize that they are short of one crystal. Evil torments them, until Ogura appears to spare the last crystal, sacrificing his life in the process.