Disc-One Final Boss

4 vs. Satan:
* Satan, surprisingly. After you beat him, someone beams the heroes in their realms where you meat the true final boss.
Alex in Princess Quest:
* NONE
The Stone of Power:
* OR: NONE
* 2: Rawn. You fight him in the ninth dungeon, but there are still two more caves left.
* RM: Artimus. You beat him and his minions, but then comes Balthar and becomes the actual final boss of the game.
The Three Kingdoms
* Palerius. You fight him mid-game only to find out someone else is responsible for the situation and has about the same game as the tyrant.
Dragondawn
* The first two dragons, whose dungeons are considerably harder than the map's other dungeons and they themselves hard to beat, but you still know there are three of them to beat.
* The last one, despite being the game's Big Bad, isn't even the final boss. You still have to escape the dungeon and then fight another boss. (Fortunately, that one is easier to beat.)
Harter Knall
* NONE
Hero Story
* Derecon and the Vampire-Lord all act as a final boss of a world, but even the player knows they're just major chess pieces of a bigger and more powerful villain.
Kill the Demons
* Casper. After you beat him, the heroes find out there is another villain in the lair. It's Rustoc, the game's actual Final Boss.
Satan Saga
* Trianuk who's set up as the first final villain, but later there are more villains the heroes have to face.
* Satan himself. Even after him, other villains continue causing carnages. As one pointed out, "Whether with or without Satan, the carnages won't stop!".
* Pope Bonmos who seems the Big Bad for the last arc, but after his defeat his king and said king's minions continue committing carnages.
Story of Hero:
* So, you failed to stop the Titan, but beat the Big Bad Elizon Tataros
The Legend of Devils
* NONE
The Sidestory Duology:
* The first game seems to play Lavius and Demonica as this, but nope, they're working under the game's main villain: Rudolf Thingy, actually Rudolf Hitler.
The Time Of Bloody Fear:
* Maltros in route four. Even after you beat him, Eldon himself becomes the main villain who masterminded the game's plot.