All Humongous Mecha Anime male and female lead characters are reincarnations from Kouji Kabuto and Sayaka Yumi.Think about it. How many Hotblooded pilots with Hotblooded Sideburns call their robot attacks are there? And how many hot-tempered Tsunderes with short supply of patience love the main character but are always arguing with him and whose robots get inevitably trashed in nearly every battle? And Shin Mazinger Zero manga did not state there were thousands of alternate timelines and worlds and Minerva-X sent Kouji back in time to prevent the end of the world? Obviously she has been sending him and Sayaka through several dimensions, but since they did not exist in some of them, they have reincarnated in the most available candidates (i.e., the Humongous Mecha pilot / Five-Man Band leader and the Tsundere / The Chick). However, a glitch happened in some dimensions, preventing their skills and tempers from manifesting completely and fully, thus diminishing their effectiveness and leading to the extinction of humankind.Final Battle in Great Mazinger he spent the next decades healing his wounds, and rebuilding his damaged face and body. However, when he was fully recovered he noticed that nobody took Humongous Mecha seriously anymore. So he created the Minovsky Particle in order to make giant mecha useful, and he worked for the first sucker he talked into hiring him (given his backstory, he would have no trouble working for someone who thinks that being compared with Hitler is flattering). Unfortunately Zeon granted him a very tight budget, so instead of Robeasts he was forced to build Zakus.
- Incidentally this means that Camille and Fa are an incarnation of Kouji and Sayaka. And the wars between The Federation and the space colonies are meaningless because, not matter who wins, an Alien Invasion will wipe all of them out.
- The alien invasion has already come and was defeated, partly by UFO Robo Grendizer but mostly by an horde of Jicco-class missile frigates built during the Mazinsaga and did most of the job in the final battle. That's why nobody took Humongous Mecha seriously anymore: conventional weapons had reached parity with them, and without Minovsky Particle they had the advantage of being simpler and cheaper to build.