"In 1987, more than forty years after World War II, the "Choujinki", an ill-fated ultimate weapon built in the final stages of the war, but never deployed, is put into action as the only hope in the battle against the merchants of darkness working in the shadows of peace and their frontline troops the Neros Empire. This is a record of Choujinki, a weapon that gave its power and limited life, not to the cause of mass death and destruction, but to peace."
— Plot summary from the DVD release.
Chōjinki Metalder ("Superhuman-Machine Metalder") is the sixth entry in Toei's Metal Heroes franchise, which aired in 1987 (lasting 39 episodes and a movie). Essentially a Spiritual Successor to Kikaider.In 1945, at the end of World War II, Professor Ryūichirō Kōga was forced into creating a super weapon for the Japanese Imperial Army. Patterning his creation to resemble his dead son Tatsuo, Professor Kōga placed his cyborg into suspended animation because of his pacifist leanings against war.42 years later, Professor Kōga's former assistant Kunio Muraki, now posing as a wealthy philanthropist named Kirihara Gōzō, has used a combination of science and alchemy to prolong his existence and to eventually attempt to raise Japan as a military nation again under his control as God Neros. Kōga decides to activate Metalder again to combat the menace.Instilled with pacifist directives, Metalder is unable to combat the threat until Kōga allows himself to be killed by the Neros Empire, which drives Metalder to seek a path of vengeance. Conflicted by both his desire for justice and his peaceful ways, Metalder, under the new "human" guise of Ryūsei Tsurugi, attempts to find a balance in his artificial life while battling the forces of evil.Metalder was one of the series that were used to create VR Troopers.
Chōjinki Metalder provides examples of the following tropes:
A.I. Is a Crapshoot: Part of the problem with the Neros Empire legion members all having different personalities is, their loyalty to God Neros varies considerably - and he's forced to realize this when Topgunder takes off on his own.
Armies Are Evil: Neros Empire's many sub-legions. (What's shocking is that the vast majority of them are present from the first episode.)
Artificial Human: Ryuusei, though he self-identifies as a Choujinki - something more than just human or robot.
Awesome McCoolname: Ryūsei Tsurugi, the name of Metalder's human guise, literally means "Shooting Star Sword". (Mai even comments on this, when they first meet.)
Awesomeness by Analysis: Metalder's battle computer apparently needs a few quiet seconds to do so, but this has led to more of his victories than anything else.
Badass: Metalder just gets more and more badass as the series progress.
Bare-Fisted Monk: Unusually for a Metal Hero, Metalder has no weapons (aside from an Imperial Navy dirk Tatsuo owned) and must rely solely on physical attacks. In a subversion, he is quick to pick up his opponent's weapons, or use something nearby.
Bittersweet Ending: Metalder wins the final battle against God Neros, but loses the ability to transform into his human form Tsurugi, keeping him in his cyborg form forever... To make it even worse, not only does he lose his Ryuusei personality, but also loses his ability to fight. He really just only barely walks away from everything.
Body Double: Coolgin turns out to be dead-ringer for Kirihara under his mask. They eventually trade places when Coolgin disguises himself as God Neros while the real God Neros escapes wearing Coolgin's armor.
Bodyguard Babes: Secretary K and S to Gozo Kirihara. They also do plainclothes spying on Ryuusei when the need arises.
Boxing Lessons for Superman: What training in martial arts does for Metalder, who is unusual amongst Metal Heroes as having zero combat skill at the start of the show. (Whether Prof. Koga just erased his pre-existing skill or never programmed him with any in the first place isn't clear.)
Co-Dragons: Coolgin, Doranga, Balsky, and Geldring; each of them is in charge of a different division of Neros Army.
Cool Bike: Metalder's Side-Phantom. (Unfortunately, the design of the costume means that, in order to operate it safely, the suit actor has to adopt a dorky pose to operate it safely.)
Cool Car: Metalder's Metal-Charger is a Mazda Familia with the ability to transform into a Flying Car.
Chuck Cunningham Syndrome: Mukimukiman and Fufuchu disappear from the rest of the series after #8. Part of the reason why they were quietly removed from the show was that they were a pair of goofy wrestlers in an army of cyborgs, mutants and armored warriors, and so stuck out like a sore thumb.
Curbstomp Battle: Coolgin managed to defeat Metalder with a single slash in their first battle. Fortunately, the damage was limited to a shoulder pad - it's visible in this page's image.
Darker and Edgier: One of the reasons the show was cut short was because younger fans were not fond of the rather dark and depressing tone of the series (or able to follow the drama-over-action writing), even for the franchise; the show is easily the darkest Metal Heroes entry. (It picked up older viewers well enough.)
Expy: Besides Metalder himself, Top Gunder is meant to be a friendlier version of Kikaider's rival Hakaider.
The story behind Topgunder was that they he was drawn up as a Armor Legion member first (a dude in a suit, not a robot), but the director saw the design and thought "Hey, he looks like a Rival"... He was consequently re-characterized as a Hakaider-esque member of the Combat Robot Legion.
A Father to His Men: It's pretty clear that Balsky and Coolgin have earned their subordinates' respect this way.
Fish Out of Temporal Water: Ryuusei was apparently programmed with knowledge of the world circa 1945... which doesn't do him much good in 1987. Being a robot though, he just visits a library. (Mai initially thinks he's an alien, name-checking ET in the process.)
Glass Cannon: Metalder is unusually fragile for a Metal Hero, and he's ended up with serious internal damage after fighting in that form.
A God Am I: God Neros obviously. The sentiment is even his first line in the show!
Grievous Harm with a Body / Deliberate Injury Gambit: In Episode 18, Zargen (a member of Neros' Combat Robot unit) stabs Metalder in the shoulder with a magnetized knife, intending to blow himself up with Metalder in a suicide bomb attack. Metalder drives the blade down to sever his arm, then he picks up his own arm and throws it at Zargen as his Finishing Move.
Heel-Face Turn: Topgunder fights with Metalder but later becomes an ally of his. Also Wisdom and her son Hedogross Jr., Ben K., and Rhapsody, all join Metalder's side after fighting the first time.
Instant Expert: Averted. Metalder starts out not knowing how to fight, and is injured in almost every episode early on.
Laser Blade: Averted, which is impressive for a Metal Hero show. Metalder's Laser Arm is his most powerful attack - and not only is it not a sword, it's not a laser either, as it's a high-frequency vibration of his arm that happens to look like one. (This also means that, by design, he can Dual Wield them.)
Legacy Character: After the original Wogger is killed, another of Neros' minions inherits his name and armor.
Martial Pacifist: Initially an Actual Pacifist (as in, he doesn't know how to fight at all), but gradually works his way up to this. He was designed under a very literal reading of this trope, and has two computers within him - his main and combat computers - which are designed to balance each other. If he (his main computer) grows as a person, so too will his combat computer.
Master Swordsman: Coolgin, who manage to defeat Metalder with one slash in their first battle.
Monster of the Week: Almost all of the villains are already shown in the Ghost Bank during the very first episode, though they're gradually eliminated throughout the course of the series as Metalder fights them or they fight each other.
Morality Chip: Prof. Koga had the good sense to give his overpowered war machine a "(Self-) Reflection Circuit" (Jisei-kairo) - and unlike Kikaider, Metalder's is fully functional.
The Movie: Ryūsei goes to a temple and learns a martial art technique in order to defeat the Tag brothers. While the movie doesn't exactly fit in into the TV series' continuity (Ryūsei speaks with his alter-ego's voice for once), it does provide Fanservice by having Mai Ōgi in a pink swimsuit.
Power Copying: Balsky, the Commander of Robotic Soldiers division, gains the ability to transform into any of his fallen subordinates during his final battle with Metalder in episode 38.
Power Makes Your Voice Deep: Unlike most toku heroes, Metalder was voiced by a different actor (Michirou Iida) than the one who played his alter-ego Tsurugi (Akira Senoo, who wasn't told why this was the case).
Rank Inflation: The Neros Army has a ranking system with ten classifications. Each division is led by a commanding officer with the title of Gaisei (Victorious Saint), while the next nine ranks below it goes from Gōshō ("Mighty General", the second highest rank) to Gekitōshi ("Light Fighter", the lowest rank). There are occasional promotions.
Replacement Goldfish: Ryuusei was built to resemble and act like Tatsuo Koga, though it becomes clear that Ryuusei is his own person.
Robotic Reveal: Ryuusei sometimes; when he gets badly injured you can see his internal systems.
Super Senses: Ryuusei's sight and hearing are far above what a normal human could even be capable of, and seem to be boosted as Metalder. His olfactory sense is relatively normal, though he can still pick up a wider range (like explosives). The Neros Empire members tend to have senses in line with their objectives.
Supervillain Lair: The Ghost Bank, which is located in the basement of the Kirihara Concern's main headquarters.