Intruder is a dragon-like creature that resides in the Ratis star.
Intruder has made several appearances in the Gradius series and set the tradition of fire elemental creatures appearing as bosses, such as Phoenix and Volleone. It is also one of the few bosses in the series to get its own theme music, a piece called "Fire Dragon" which plays during its reappearance in the Gradius II boss rush stage. Curiously, it appears as only a sub boss in the NES port of Life Force.
In the Japanese version of Life Force, Intruder, like the stage it's in, has been recolored blue.
Its weakpoint is its head.
Intruder will attempt to wrap himself round the player, occasionally breathing fire. In the original game, Intruder's movements are fairly jerky and stiff, owing to limited programming of the era, but later games refined the programming to give it more fluid snakelike movement. In some games, Intruder can physically crush the player with its body. Since it has relatively low health however this is somewhat unlikely.
In Gradius II, it gains a new ability - splitting into three at low health. This naturally greatly increases the difficulty of the boss, each head needing to be eliminated on their own.
- There are smaller fire dragons that reside in other stars, suggesting several stages in the life cycle of this creature. These range from the smaller, weaker Fire Dragons that reside in small scale suns, to the multiheaded Vulture Dragon.
- Similar looking creatures are used as living weapons in the Core Warship Deltatry, perhaps even the same species. These particular dragons turn on their master upon his defeat, suggesting cruel treatment.
- A spell called "Salamander" in Castlevania: Portrait Of Ruin summons an Intruder-like dragon that circles around its target, dealing massive fire damage.
- In the Yu-Gi-Oh! card game, there is a monster similar to this one called Solar Flare Dragon.
|Stages (Arcade)||Burning Heat • Synthetic Life • Crystal World • A Way Out of the Difficulty • The Old Stone Age • Deprived Sanctity (PC-E exclusive) • Maximum Speed • Boss Rush • Into Hostile Ship|
|Stages (NES)||Stage 1 • Stage 2 • Stage 3 • Stage 4 • Stage 5 • Stage 6 • Stage 7 • Stage 8|
|Bosses||Phoenix • Big Eye • Giga (NES) • Crystal Core • Death MK II • Jumping Moai • Big Moai • Desert Core (PC Engine) • Big Core MK II • Zub Rush • Big Core • Tetran • Gau • Intruder • Zelos Force (NES) • Covered Core • Demos • Crab • Gofer|
|Space Entities||Nucleus • Intruder • Invader • Phoenix (Geezer Butler) • Goliath • Bubble Eye • Wyvern • Vulture Dragon • Blizzard Crawler • Chimera • Gillador • Volleone • Biological Organism • Lynyrd Skynyrd • Triumph Kicks • Gau • Giga|
|Body Horror||Abadon • Brain Golem • Big Eye • Gregol • Mad Skin • Brachion Eye • Biter • Berial • Huge Heart • Crawler (X) • Infected Statue|
|Plant Life||Choking Weed • Stinger Kid • Hunter Fang • Giga's Rose • Dendrodium • Hans Naughty|
|Living Cores||Zylom • Killer Dwarf|