The Unknown Soldiers or Marines are a duo of anonymous main heroes in 1988 classic arcade scrolling shooter video game titled Forgotten Worlds (Lost Worlds in Japan), the third and final entry in Capcom's "jet pack" shoot 'em up series along with 2 installments: Section Z and Side Arms Hyper Dyne.
In the first appearance of both of this playable duo, they don't have their actual names given, but all were known to very generically. Where Unknown Soldier Blue represents the first player and Unknown Soldier Red represents the second player.
As the young ones did in the past, they were secretly trained by a group of human beings to resist the evil forces on the future setting called the Dust Planet. Many years passed away since humankind has ruled the Earth, the extraterrestrial invaders have nearly attacked there in their attempt to include it to their evil empire. The dark emperor Bios has controlled the alien horde to crush all oppositions. Through the game, the duo of Unknown Soldiers are the last hope and they must face their assault on their enemies in personal, deadly combat. They are also equipped with an anti-gravity device and armed with photon guns to seek and destroy the ruthless minions of the evil Empire. In their attempt to overthrow Emperor Bios, they will battle the strangest and strongest extraterrestrial creatures across the universe like the lizard men, the shapeless creatures, the fierce bronze-skinned dragon and even deities. However, they are not completely alone in their quest for universal freedom. In order to provide their goals, they can upgrade their weapons systems, armor, items, medicines and the important information for a cost of Zenny in certain locations scattered throughout the lands around the universe with Sylphie, a female weapons dealer who must praise the victory over the evil hands of Lord Bios once the world is freed from extinction.
As in the actual ending, the duo didn't have any names other than so-called "Superior Warriors".
Outside of Forgotten Worlds, the Unknown Soldier 1P made the other appearances in few crossover games, such as Marvel vs. Capcom: Clash of Super Heroes (where he is also known as "Unknown Soldier"), Capcom World 2, SNK vs. Capcom: Card Fighters Clash and Namco X Capcom with the Unknown Soldier 2P (both of them are being playable allies).