Sometime between the events of Gradius III and Gradius IV, the Gradius Empire got into a confrontation with the Bacterians. Unlike previous encounters however, the Bacterians used more advanced technology, making them much more prepared for an assault against Gradius. To counter this however, the Gradius Empire deploys not only the Vic Viper to stop the evil empire, but also the Lord British, as well as to newly released fighters called the Jade Knight and the Falchion β; each of the four fighters has their strengths and their weaknesses, making them useful for different approaches to stop the imminent invasion.
All four crafts travel across familiar and unfamiliar worlds, where they all encounter and defeat various Bacterian troops. Afterwards, they locate the source in the Black Nebula and destroy it whilst narrowly escaping destruction, bringing an end to the Bacterians once more.
- Length: 14.55 m (47.74 ft)
- Wingspan: 23.58 m (77.36 ft)
- Height: 6.03 m (19.8 ft)
- Crew: 1
- Max Speed: 5.70c
- Drive: M-3 Antimatter Engine x2
Unlike the Vic Viper and the Lord British, the Jade Knight uses more strategic weapons in battle.
- Laser Cannon - a standard, semi-automatic laser bolt that can deal with smaller Bacterians easily.
- Spread Missle - fires a single missile that drops at an arc, upon making contact with any surface, the missile explodes, creating a medium-sized explosion that destroys enemies in its radius.
- Round Laser - a new, unusual laser that is unique to the Jade Knight. The Laser creates a green ring around the Jade Knight, which is not only very powerful, but also allows the craft to attack Bacterians from the flanks.
- Pulse Laser - another laser which fires two standard green laser bolts straightforward, essentially doubling the firepower of the Jade Knight, however the bolts are not very powerful.
- Options - creates an orange, orb-like satellite that follows behind the Jade Knight's trail that increases the firepower of the craft by one unit, but does not provide shielding protection; up to four can be obtained at maximum.
- Shield - creates a shield that protects the Jade Knight by various means, depending on the type of shield the pilot sets up, it will be one of the following:
- Shield - creates two hexagonal gears that protect the Jade Knight from the front for a significant number of hits, but leaves the other sides exposed.
- Force Field - creates a shield that covers the entire craft, but only protects it for about half as many hits as the normal shield.
- Guard - a new type of shield introduced in Gradius Gaiden, it grants the Jade Knight protection from the top and bottom of the craft, but can only absorb two hits. It also grants the ability to negate collision with terrain.
- A Yu-Gi-Oh card of the same name exists, and is based on Jade Knight.
- The Jade Knight, along with the other Gradius Gaiden ships, have a kind of hyper-drive system than allows them to travel faster than light for escape of the Black Hole in the Stage 7.
- Jade Knight's original ship name was GrayLayer.