The Iridion is the villainous force from the Iridion series. It is an alien force from the far reaches of the galaxy, which without warning invades Earth and successfully takes over, leaving it's forces positioned on the ocean and atmosphere. A pilot of the experimental SHN fighter, which was testing the ship, returns to Earth only to find the planet taken over by the Iridion forces, so he decides to fight against them. He defeats the invading forces, reaching into the sky and the planet's orbit, and following them to the moon. With the invasion crushed, the SHN proceeds to follow the forces to their home planet, Iridion Prime, where he destroys the Mainframe controlling the Iridion forces. With it's destruction, the remaining forces disappeared.
A hundred years passed since the invasion, and humanity began to colonize the planet systems on the Iridion galaxy. Peace is disturbed again, as the Iridion returns, and starts reclaiming it's planets. Since Earth was too distant to send help in time, a pilot is assigned to the SHN fighter and sent to fight back the Iridion forces. He successfully liberates the planets taken over by the Iridion, following them into their new headquarters, where he destroys the Iridion mainframe, once again putting an end to Iridion's schemes.