Fire LEO is a series of star fighter featured in all installments of Thunder Force series. Several variants have been built by the Galaxy Federation as a defense line against the ORN Empire under the codename called "Project Thunder Force".
List of Fire LEO variants
Fire LEO - this starfighter was built for 2 purposes: Locate and destroy the Shield generators of the ORN fortress Dyradeizer. The plan succeeded with the destruction of Dyradeizer.
Fire LEO-02 "Exceliza"(also known as Excelizer) - the Galaxy Federation learns that ORN houses Plealos deep below Nebula's surface when not in use and takes the opportunity to plan an operation to take it down. They send the next iteration of their Fire LEO series of fighter craft, the Fire LEO-02 "Exceliza", to destroy ORN bases on Nepura and eventually find and destroy Plealos. The player controls the Exceliza and travels through a variety of stages to accomplish this goal. According to the Genesis US package, the pilots of this unit are Ryder Jupiter and Diana Rean.
Fire LEO-03 "Styx" - it was created as a craft small enough to avoid detection by Cerberus, but equipped with the firepower of a large starfighter. It was deployed on a mission to destroy the five cloaking devices installed by the ORN Empire in five different planets, infiltrate the Empire's headquarters, and destroy its emperor, the bio-computer "Cha Os".
Fire LEO-04 "Rynex" / Vastian's Steel / Vasteel - with an initial defeat, the Galaxy Federation develop this small and powerful craft to fight back the forces of Vios. Right after the accomplishment of the mission, the Vios fortress massive explosion heavily damaged the ship, but didn't destroyed it, leaving it drifting through space until it reached the Oort cloud, where it was discovered by the EASA Space Probe "Sekika 3", the humans know this discovery as the "Vastian's Steel" or "Vasteel", its discovery triggered an evolution in Earth's technology known as "Vasteel Technology", but also unleashed a war against the human race. Rynex was destroyed by the RVR-02 "Vambrace" during a battle against the Sword Fleet. The Rynex pilots were Roy S. Mercury and Carol T. Mars, it is unknown who piloted it when it was rebuilt as Vasteel Original, it could be controlled by the Guardian, but there's no clues about that.
Fire LEO-04C / Fire LEO-04改 "Rynex-R" - Galaxy Federation researchers managed to take advantage of the original Rynex's design and successfully mass-produced the craft in large quantities. The ship needs specific amount of skill to pilot it. The Thunder Sword add-on is now implemented from the start, though it is inferior to the destructive power employed by the original. However the ship makes up for this by strengthening diversion of each armaments. Gene S. Mercury is one of the pilots of this fighters.
Fire LEO-05P "Syrinx" - due to the cancellation of Thunder Force VI on the Sega Dreamcast, they can only speculate about this ship. Unlike the traditional red colors of the Fire LEO's, the Syrinx featured an RVR like color scheme, which will make us think of a possible Earth-Galaxy Federation joint project. This ship can fold its wings for shift from Attack Mode to Speed Mode. Due to the cancellation of the game, the identity of its pilot is a mystery.