The Rivalry of Radiguet and Tranza
Compared to the rather comedic rivalry of Ryuon and Gaja, this one is no laughing matter. As we know it, Radiguet just NEVER will allow anybody to rule over him and he hates having somebody rule over him. He's one cruel sadist with a self-righteous outlook in life (he believes he has the right to eradicate everyone for being bastards when in fact, he is a real bastard) and in fact, everything about this guy is clear to the point that Radiguet will never tolerate competition.
Obviously while Tranza was still Tran, Radiguet had frequently bullied him or mistreated him. Tran wanted revenge and in a matter of hours or so, in Jetman episode 36 at the end of it he accelerated his growth to become Emperor Tranza. I have to admit that Tranza was one incredibly bad braggart with real subtle skills. So yeah, he was getting his revenge on Radiguet for bullying him without even being aware that Radiguet may sooner or later beat him out of insanity. His first act as a grown up man was to actually inflict Radiguet, Maria and Gure with pain so he can all bully them as they did to him. But Radiguet wasn't going to let some brat who suddenly grew up beat him! He had some plans to get rid of his rivalry and of course for Radiguet, he feels he's the only one allowed to kill the Jetmen! What was worse was that, Tranza overruled them and Radiguet was reduced to being a servant AGAIN which he hated.
It's obvious these two hated each other. After all, who wouldn't want to get even with somebody who bullied you a lot? Tranza was getting it and Radiguet was feeling it. To Radiguet he's obviously, "Nobody dethrones me as the most feared person! I decide who lives and who dies!" in his psychologically insane mind that wants nothing more than to rule everything under him. The rivalry got so intense when Radiguet created the Meteor BEM (but Tranza managed to bounce back at him) and later the Demon Robot Veronica. But Radiguet was never actually done. In fact, during the Veronica Crisis, Radiguet's hatred there again made him help the Jetmen (so he could kill them later), and two, he really HATED Tranza. While Tranza fed him to the Demon Robot Veronica, ironically Radiguet absorbed its energies making him even crazier than he already was.
Well this led to Radiguet plotting Tranza's downfall behind the scenes. For a guy who's batshit crazy, he sure still can plan something as well orchestrated as this. I mean, most of the time Radiguet is too much "Kill, smash, destroy, rend, mangle, distort..." against the Jetmen and his enemies, but you have to admit that this was his best plan ever aside from claiming the Jetmen's souls. In the process, Ryu was deceived by Radiguet (well he never saw Radiguet as a human) and he planned Tranza's downfall. Tranza was defeated by Radiguet's dirty trick now it was time for the final confrontation.
Yup, Radiguet shows just how much of a sadistic bastard he is. I thought really, come on kill him! Before he does anything to the now defeated Tranza, he makes him declare him as Lord Radiguet, which he took pleasure in doing so. I thought it was pretty cruel for Radiguet to pin Tranza's organic hand to the ground with a sword just for the heck of it, and he smiles while doing it! Radiguet leaves Tranza dying and of course this is what we see of Tranza according to canon was pretty grim.
Tranza was reduced to nothing more than a vegetable at the end of Jetman, his fate unknown as of current. He was admitted into the mental institution where he will probably remain for the rest of his life. This was really a disturbing scene to see that Radiguet had gone more cruel than he already was, ending their rivalry in a very neat and satisfying manner. Tranza was in his most pathetic state at best.
In the non-canon Manga, Radiguet went as far as to possess Tranza's body and returned to cause trouble with it. Well for one, Tranza later backfired (again) and this time, it led to his final downfall. But that of course was part of the non-canon Manga which contradicted the events of the Jetman Encyclopedia (where Ryu and Kaori had a son named Gai Tendo instead of a daughter named Aya Tendo in the Manga). Despite it being non-canon, it still shared an interesting side of their hatred for each other.