Perhaps I should say "championing the obscure since 1983" in my title box.
The "Metal Heroes" are simply a bunch of tokusatsu series (i.e. Japanese special effects-driven live action) produced by Toei.
They start with Gavan, a series about a "space sheriff" who fights a space crime organization.
Considering the resources at their disposal, he's pretty impressive, right?
Most early Metal Heroes were pretty much the same-in fact, the original three series were all thought of as a trilogy, and their protagonists' equipment were functionally nigh-identical.
This continued until Metalder, which has been described as an homage and spiritual remake of an older series called Kikaider.
Incidentally, there was apparently a scene in Metalder where the robotic protagonist forced his enemy to sever his (Metalder's) own arm in order to break free, and then used said arm as a spear to impale the same foe. (A clip was once on YouTube, but that user has apparently been banned.) Note also that Metalder and several of the other early Metal Heroes series were used to create the short-lived Power Rangers-like series VR Troopers, which was originally intended to star the actor Jason David Frank, who played the Green Ranger in Power Rangers.
Similarly off-formula was Jiraiya (no, not that Jiraiya-both characters were based on this folklore character), who showed a portion of his face and didn't even wear full plate armor.
The series then turned away somewhat from many traditional tokusatsu aspects with Winspector and its immediate successors, which were closer to traditional cop/rescue worker series in formula (at least, if what I've read is any indication) in that there was no single enormous villain organization.
It also had several robot characters who would be impossible to distinguish from their human counterpart (in the sense of general appearance) if they didn't act like total spazzes.
The next turn was towards an almost super sentai/Power Rangers-like dynamic, with animal-themed powers and characters, particularly beetles.
This series and its immediate successor, B-Fighter Kabuto, were adapted into Big Bad Beetleborgs, a cheesy, almost Adam West Batman style series that featured kid superheroes hanging out with Universal Monster knockoffs living in a haunted house. (It wasn't great, but it was much better than you'd think.)
And then, it took another turn.
This is where I might go "WHAT IS THIS I DON'T EVEN" if I were being surprised. Kabutack and its successor Robotack (which starred a dog robot) were even more kiddie than the Beetleborgs adaptations, as far as I can tell.
While this isn't innately a bad thing, Metal Heroes ended there, and it hasn't come back (except in the Philippines).
And that's kind of sad, if for no other reason than because it means that there are now only two extremely long running Toei tokusatsu metaseries in Japan (Kamen/Masked Rider and Super Sentai).
I'm not the only person who thinks that's a shame, right? Right?