Ogura is the main antagonist of Densetsu no Stafy and Densetsu no Stafy 2, as well as a secondary antagonist in Densetsu no Stafy 3. He is an evil demonic eel who set out to conquer Pufftop long ago though was imprisoned in a jar by a young Papa Star. It is revealed in Stafy 3, that he was enslaved by Evil when he was younger, and that is the reason for his villainy.
Densetsu no Stafy
While carrying treasure, Starfy accidentally dropped the jar, releasing Ogura from his imprisonment. Ogura then used his magical powers to create a terrible storm and terrorize Pufftop.
At the end of the game he is defeated by Starfy and re-sealed within the jar, though soon afterwards Starfy accidentally trips and knocks over 45 treasure chests. Until all the treasure chests have been collected, Starfy will make the mistake of knocking over the jar and re-releasing Ogura.
Densetsu no Stafy 2
In Stafy 2 Ogura creates the Puchi Ogura from two black orbs he dispenses from his nose. The Puchi Ogura escape from the jar and cause another storm to hit Pufftop. The storm knocks over the jar and releases Ogura. Ogura then kidnapped Mama Star as revenge for being trapped inside of the jar.
After defeating the Puchi Ogura, Starfy fought Ogura and once again imprisoned Ogura in the jar.
Densetsu no Stafy 3
In Stafy 3, Evil destroyed the jar, freeing Ogura permanently. Ogura then met with Evil, who gave him one last chance to conquer Pufftop. Evil then altered Ogura's appearance to make him stronger.
In this game he is fought as the penultimate boss. After being defeated, Starfy and his friends proceed on to fight Evil.
When Starfy, Moe and Starly reach Old Castle where Evil resides, they discover that in order to truly defeat Evil, they need to collect all 42 Evil Crystals.
Despite only having 41 they confront Evil anyway. Things look bad until Ogura appears and reveals the last Evil Crystal, sacrificing himself to finally destroy Evil.
In the Starfy manga, he is noticeably more evil. He lacks the sympathetic backstory, as Evil does not exist in this canon, and acts on his own accord. In his first appearance he attempts to choke Starfy to death, establishing his more brutal character. He is Pure Evil in this canon.