Genre Savvy: Prof. Yumi was pretty Genre Savvy. For example, he made sure they got spare parts for Mazinger-Z ready to be used in case of an emergency (during one battle Mazinger had lost his fists and they launched spare Rocket Punches at its location to help Kouji). In one episode he hesitated several persons were dead why their corpses were not found. And he memorized the plans for the Jet Scrander in case of they were stolen (and indeed, they were).
Get a Hold of Yourself, Man!: Subverted. Sometimes Kouji slapped Sayaka to try to calm her down or get her out of a Heroic B.S.O.D. (it happened as soon as episode 7). However, given that he is infamously tactless, it did not work. The only thing it accomplished was getting her mad -or madder-.
Giant Enemy Crab: Zarigan G8 was a Mechanical Beast shaped like a orange-and-red giant crab with large eyes and a long tail. It was amazingly fast and agile underwater and beat the crab out of Mazinger-Z -that had always been a lousy fighter underwater- during their battle.
Giant Equals Invincible: For the most part it is played straight. In the first episode Garada K7 and Doublas M2 are trashing a city. Bullets, missiles, tanks, jets are thrown in their way... and they not even put a dent in their armor plates. It is not until Mazinger shows up they are trashed in turn. However, FemBots are not invincible -even if they were crushed by other giant robots- and sometimes Aphrodite A was overwhelmed and briefly deterred by an army of Iron Masks using conventional weapons.
Subverted when Kouji destroyed one of the Mechanical Monsters of Archduke Gorgon using landmines -even though it was supposed to be stronger than Dr. Hell's Mechanical Monsters!-.
Giant Robot Hands Save Lives: Several examples. A particularly awesome instance happened in the episode 28 when Mazinger Z saved Professor Yumi with a Rocket Punch when he was falling down a cliff. In the Ota equivalent manga chapter, he was faling from a flying fortress and Aphrodite A was the one caught him.
The Glomp: Sayaka used it several times in many manga versions and continuities (albeit not so much in the anime adaptation). Remarkably, she resorts to them when Kouji is feeling gloomy. Her reaction when she met Kouji again after the Final Battle in the Gosaku Ota manga? Glomping him. Her reaction in the Shin Mazinger Zero manga when Kouji got a I Am a Monster moment? Glomping him as declaring he is her ideal man.
Erika used The Glomp with Kouji in episode 63, much to Sayaka's jealous wrath.
Glowing Eyes of Doom: When the eyes of Mazinger Z glowed, you knew you had to run for cover. Often it happened when Kouji was really, REALLY fired up or even panicked or in danger, and somehow his state of mood affected his mecha (which suggests Mazinger was sentient, a point plot later versions have explored). A memorable example happened in Shin Mazinger Zero. Mazinger was chained by a Robeast and unable to get free as another Mechanical Beast was disintegrating Sayaka'sHumongous Mecha. Then Kouji got REAL MAD, and Mazinger's eyes glowed right before he shattered the chains binding it and delivered a Curb-Stomp Battle to both Robeasts.
Goodbye, Cruel World!: In episode 46 a woman left her baby son together with a suicide note on the Institute's doorstep, explaining that her husband had passed away and she had got ill and could not take care of their son anymore so she had left him on the only place on Japan where she thought that he would be safe before killing herself. After finding the note the characters hurried up to search her around the grounds of the Institute.
Grand Finale: At the end of the series, the group has finally located Hell's base, and they head towards there, supported by the Japanese army (in the Go Nagai manga, an army of Mass-Production Mazingers was produced; Hell's counterattack was sending a fleet of seventy Mechanical Beasts, a submarine and an aerial fortress to imvade and take over Japan in ten days). Mazinger, Aphrodite-A and Boss Borot duel against Hell's last Mechanical Beasts and start trashing his Base. Hell gets fed up and decides blowing his island up and fleeing on board of his aerial fortress. Mazinger goes after him and they engage in a last aerial duel. After winning, the heroes return to their Home Base, believing they are safe at last, but Dragon with an Agenda Archduke Gorgon sends two War Beasts behind them. Gorgon's Robeasts easily destroy the three Humongous Mecha and raze the Institute to rubble, but before they could kill Kouji, another Robot shows up and easily annihilates the Beasts, hinting the sequel.
After a fashion. Minerva X was designed by Professor Kabuto, but never actually built; Dr. Hell got his hands on the plans and constructed Minerva, using mundane armor materials instead of Super Alloy Z, and installing an AI "crown" piece in place of a Pilder.
And in the "The Relic of Evil" one-shot, Mazinger-Z itself was hijacked by a Kedora sent by Dr. Hell.
Gratuitous English: The Toei dub has theme songs sung entirely in English by famed anime singer Isao Sasaki.
Though not nearly as gratuitous as the version Ichiro Mizuki did, which was pretty much nonsensical.
Gratuitous German: Count Brocken was German and sometimes into the Gosaku Ota episodes he fell into uttering some sentence his native idiom ("Gutten Abend").
Gratuitous Ninja: In episode 46 Dr. Hell decided changing his usual strategy and instead of two Humongous Mecha he created two three-meters-tall ninja robots (the Blazas S1 and S2 "brothers") to carry a sabotaging mission off. They could perform complicated acrobatics, and threw shurikens -as well as missiles-. There was no apparent mission for them being ninjas other than ninjas are cool.
Greater Scope Villain: The Emperor of Darkness. The Humongous MechaBig Bad Dr. Hell found were ancient and severely outdated weapons of his army. During the first series he did not directly interfere with the plot, and he remained in his underground empire, watching the war between Kouji Kabuto and Dr. Hell as one of his underlying schemes to bring both of them down. After causing the end of Dr. Hell's army and Mazinger-Z he became Big Bad of the next series.
Green Aesop: Several times we were given messages about the dangers of depleting the planet's natural resources and polluting the environment. They were not subtle. AT ALL.
In episode 34, Kikaijuu Genocyder F9 had troubles shattering the Home Base's Deflector Shield, so it ripped its own arm off and threw it against the barrier. The ensuing explosion succesfully destroyed the energy shield, and Genocyder's missiles pummeled the place flat.
In Shin Mazinger, Zeus gets his arm cut off by Hades. When he sees Mazinger Z use a Rocket Punch later in the episode, he's so impressed that he picks up his own severed arm and throws it while shouting "ROCKETTO PAAAANCH!!"
Gut Punch: The last third of the anime series was getting increasingly darker due to the new enemies: Professor Morimori was murdered, Aphrodite A was definitely destroyed -which, believe it or not, was a great deal and Sayaka got an Heroic B.S.O.D. cause it-, Kouji and Shiro's mother returned only to be revealed she was an imposter -poor Shiro was forced to shoot her in spite of he was not sure of she was not his real mother-... and then you have the final episode: the heroes have triumphed over Dr. Hell and return to his Home Base... only to find out tht one of the Co-Dragons was secretely working for a Greater Scope Villain. Two unknown Robeasts appear, easily destroy the Institute, Diana-A and Boss Borot, and when Kouji goes to fight them, they easily and mercilessly trash the erstwhile apparently invincible Mazinger-Z.
This episode was better developed in theMazinger-Z vs Great General of Darkness feature. Five major world cities destroyed in one single day, Shiro wounded cause a crumbling ceiling and falling into a coma, Kouji deploying Mazinger, in spite of he is injured and weakened and his robot unrepaired and power-depleted, and being soundly trounced... Great General of Darkness had an excellent The Dragon curriculum.
Ham-to-Ham Combat: In the Dynamic Heroes e-manga, Kouji Kabuto fought Great Marshall Of Hell as riding Mazinger. It is noteworthy as it was, maybe, the first time in the history of the franchise Kouji and Dr. Hell faced each other directly as both were riding giant robots. Too bad it was a Curb-Stomp Battle.
Held Gaze: Kouji and Sayaka do this in the Mazinger-Z vs Great General of Darkness, right when Kouji is going to sortie with Mazinger-Z to fight a battle he knows he can not win, and thinking he'll die. Sayaka stops him to give him his little brother's birthday gift, and both stare into each other's eyes for a long while. In the movie, Kouji finally turns around and leaves. In the manga version of that moment, they DO kiss.
Here We Go Again: The series ends up right like it began: a mysterious army of Robeasts attacks the Photon Atomic Power Research Institute, and they are defeated by the sudden appearance of a Super Robot named Mazinger the enemy knew nothing about. Cue the sequel starting the next week in the same time slot.
Heroes Prefer Swords: Subversion. In spite of the fact that swords are common Humongous Mecha weapons, Kouji never used one (unless you count the Iron Cutter weapon he got in the last seasons). His sucessor, Tetsuya, was the one who introduced the trope in Super Robot Genre.
Heroic B.S.O.D.: Sayaka, after Aphrodite A is destroyed. She even almost drowns herself in a lake when she thinks she's hearing Aphrodite calling out to her from there.
She had another way earlier, in episode 7. A mob -enraged at having their hometown leveled by two battling Humongous Mecha- threw stones at her father, landing him in the hospital, and almost broke into the Institute. She was so upset and distraught she considered to stop fighting.
And in the original manga, Kouji has another in an early chapter after being forced to kill an Iron Mask. He remained kneeling and shaking.
Heroic Resolve: Kouji has plenty moments like this. Threatens someone innocents and he will go The Berserker. A good example happens in Shin Mazinger Zero: The Dragon Baron Ashura has managed gets Mazinger-Z and Aphrodite-A trapped, but instead of ordering one of his Mechanical Beasts targeting Kouji he orders it targeting Sayaka because she pissed him off (by wrecking THREE of his Beasts), so he wants to kill her as Kouji witness it helplessly. It was NOT a good idea (You do not know what an Unstoppable Rage is until you see an angry Kouji charging).
Heroic Sacrifice: ... Just one too many. Specially in the Mazinkaiser movie. Subverted by Boss at an early stage - he self-destructs the Boss Borot, but shows up a short while later asking "Why do I have to die for you, Kouji!?"
And in episode 74 Sayaka sacrifices Aphrodita-A to save Kouji.
Heroic Second Wind: Kouji got several of them through the series, and the first of them happened as soon as the second episode. He barely know how piloting his mecha and he was being soundly beaten by Garada K7 and Doublas M2. Finally he got knocked out and Doublas M2 proceeded to torch Mazinger with him inside. However, as he was unconscious, he saw or believed seeing his grandfather's spirit reminding him because he was fighting and what were the consequences of being defeated. Kouji came around, got up and started to trash both Mechanical Beasts using Mazinger's weapons.
Heroic Spirit: Kouji Kabuto will keep fighting even if he is badly wounded and weakened, his weapons have been destroyed, his Humongous Mecha is running out of power, he is outnumbered and the enemy is way more powerful than him. The times he has almost or fully crossed the Despair Event Horizon his mindset has been "I am going to die... Alright. I'll die fighting." However Sayaka's Heroic Spirit is even greater because she knows she is always underpowered. She is nearly always badly beaten in battles and still keeps fighting.
It is hinted in the original series and more heavily in other relatedseries that the "God or demon" Dr. Kabuto lecture refers to Mazinger-Z's power depending on Kouji's Heroic Spirit. If Kouji is in The Determinator mode and wants to save the world, Mazinger will even move on its own to save Kouji. If Kouji has crossed the Despair Event Horizonit will become a demon.
Hero Killer: All heroes -and even his allies- are scared of Archduke Gorgon. He is strong, physically imposing, ruthless, and neither of them can beat him in a fight. The only character refused to shrink back from him was Pygman.
High-Altitude Battle: As soon as Mazinger-Z got a flying upgrade -right in that same episode- Kouji got a high-altitude battle against a rocket-shaped, missile-shooting Robeast. It was the first of many.
In another episode, the enemy tried to force Kouji to fight several dozens of feet above the ground so that Kouji's body and Mazinger's machinery were unable to endure the physical strain.
Highly Visible Ninja: Blazas S1 and S2 were two ninja MechaMooks than Big Bad built for a sabotaging mission in episode 46. They were actually pretty stealthy when they infiltrated into the Institute... but when they had to chase a target or fight Mazinger they used all kind of flashy movements, jumps and sommersaults, making a pose as they threw shuriken and shot missiles and being incredibly loud. Needless to say, their blue-and yellow colors did not help to camouflage themselves in a woodland.
Hope Is Scary: In Shin Mazinger Zero Minerva-X is locked into a Groundhog Peggy Sue loop where she sends Kouji Kabuto back in time to save the world, he fails and she sends him back again. Until now she has failed 2,798 times towards averting the End of the World as We Know It. She does as much as stating all of those times she hoped, and her hope was in vain. However, in the current timeline she is stuck in, she is seeing signs of maybe -maybe- things will finally be different this time around. So she feels a glimmer of hope... and she is afraid of being hopeful only for getting disappointed and heart-broken again.
Hot Springs Episode: In chapter 8 of the original manga, Kouji and his friends spending a while on a hot springs resort in a mountain. That episode was noteworthy because Mazinger-Z did not show up and it had a very funny Kouji/Sayaka moment in the hot springs (with a double Luminescent Blush included).
Hoist by His Own Petard: Dr. Hell designed a Mechanical Beast (Spartan K5) resembled a gladiator but it was a pacifist refused attacking unless provoked. Baron Ashura decided testing it against Mazinger Z, but Kouji actually befriended it. Enraged, Ashura ordered several Iron Masks putting a time bomb on Spartan K5 to blowing it up. Later, Spartan was accidentally goaded into attacking Mazinger Z and UTTERLY BEAT THE CRAP OUT OF IT. It was about of delivering the final blow when the bomb went off. Kouji and his friends felt sad. Hell and Ashura threw a fit.
A nearly literal example in another episode. Kouji was fighting the Mechanical Beast Glossam X2 in a an underwater battle. Glossam shot a pair of torpedoes at Mazinger. Mazinger grabbed them and threw them back, blowing Glossam up.
In episode 27, Ashura captures Aphrodite A and scans it in order to learn how building a photong engine. He hands over the records to an Iron Mask and commands him go and hand them out to Dr. Hell. Though, a Kikaiju -that had been deployed by Ashura to delay Mazinger Z- is returning to base right on that moment, and steps on the Iron Mask, killing him and ruining the records.
Home Base: The Photon Atomic Research Institute was the heroes's base where they kept the Humongous Mecha and all tools they needed to repair and upgrade them. Originally it was a civilian use building -a laboratory researching the newly discovered Photon Atomic energy-, but Dr. Hell pretty much forced them to make some modifications (such like installing a Beehive Barrier). Over the half of the series, The Hero and his little brother moved to the Institute, making the example even more literal. Big Bad Dr. Hell had two Super Villain Lair's Bardos Island And Hell Island. Both of them counted as Elaborate Underground Base, Island Base and Mad Scientist Laboratory.
Island Base: Like noted above, Dr. Hell had two Island Bases: Bardos, an ancient Greek island full of underground mazes and labyrinths where he found an army of Humongous Mecha: and Hell Island, an island near from the Japanese coast where he moved later in the series. It was a barren, rocky islet. A low mountain rose in the center, and several giant faces had been carved on its slopes. Baron Ashura's submarine fortress Salude doubled as both an Island Base and Cool Ship.
Hope Spot: Several of them. Maybe the best remembered ones are:
In episode 91, finally the main characters defeat Dr. Hell. Naturally, they think the war is over and they have finally achieved peace. However, the music playing during the last scenes is eerie, and the narrator voice reminds the viewers that Archduke Gorgon is still alive, and he warns the heroes are about of facing the worst battle of their lives. In the next episode, two Mykene War Beasts, more powerful anything Hell had ever constructed, utterly crush the heroes and destroy their Home Base.
In episode 92, Sayaka and Boss are fighting the War Beasts and being utterly trounced. Then Kouji finally shows up... and the War Beasts tear through his Humongous Mecha like if Mazinger-Z was made of paper instead of Made of Indestructium.
In the Mazinger-Z vs Great General of Darkness feature Kouji is fighting an army of Mykene War Beasts... and getting completely trashed. Out of helplessness, the main characters launch Boss Borot. Boss' Humongous Mecha crashes into a Beast was previosuly thought of like invulnerable, and he manages blowing it up, saving Mazinger. The main characters cheer up... right before another War Beast swats Boss away with a single blow, and the Mykene army keeps on tearing an utterly helpless Mazinger apart.
In the Gosaku Ota manga episodes, Mazinger-Z is trashing Hell's Super Villain Lair. Hell is out of Robeasts, out of Co-Dragons, out of troops, out of traps and out of tricks. Suddenly Archduke Gorgon shows up, commanding two War Beasts proceed to soundly trash Mazinger-Z, and Hell laughs thinking he has won at last. And then Gorgon backstabs him. Literally.
How Dare You Die on Me!: In episode 52, Kouji gets brutally hurt during a fight and falls unconscious. When he does not move or reacts, Sayaka gets grief-stricken. She kneels by his side, and she starts crying as holding him in arms. She pleads him not dying and not leaving her alone, and even makes an Anguished Declaration of Love. Then Kouji opens his eyes and he announces he is not getting married to a tomboy. Cue Sayaka wanting killing him for real.
Several times Kouji said (in the original manga) that he does not believe in ghosts or living corpses. Then in a Crossover movie with ''Devilman, he accidentally wakes up a demon and spends the remain of the movie finding and fighting demons and devils.
Huge Guy, Tiny Girl: Inverted in New Mazinger. Major Kabuto is human-sized. Princess Krishna is Mazinger-sized (around eighteen-meters tall). He -understandably- complains she is the most beautiful woman he has found, but they are the wrong size.
Human Aliens: In this universe, the Fleedian race look completely human. On the other hand, the aspect of the Vegans varies wildly. Emperor Vega seemed a hairy, pointy-eared, pig-nosed monster, but his daughter Rubina mostly seemed human. Other alien races in this universe range of monster-like to human-looking but with unusual hair, skin or/and eyes colour (like secondary character Menao).
I Control My Minions Through...: Dr. Hell controlled his lackeys through a mix of Acceptance, Loyalty, Mind Control and Sadism. All his troops were brainwashed cyborgs and his Robeasts were mindless monsters controlled through a remote control. Most of his Co-Dragons were loyal mostly because they were alive thanks to him... and because he punished disloyalty and failure harshly (he always avoided You Have Failed Me scenarios, though). Those who were not mind-controlled or afraid of his power and sadism, though, were prone to rebel and in the case of Gorgon, he responded to another authority altogether.
I Miss Mom: Shiro is a ten-year-old kid who lost his parents when he was barely a baby. He misses them -and his older brother Kouji in Great Mazinger-, but he mainly and badly misses his mother. How badly? The tile of an episode is "Shiro misses his mother" (at least in the Latin dubbing). In that episode, a woman came to the Institute claiming she was Kouji and Shiro's mother and wants to get reunited with their children again. Kouji was -rightfully- suspicious, but Shiro was too glad and happy for questioning anything.
Ignored Expert: Subverted by Dr. Kabuto. Despite the fact that he was a renowned scientist and a witness, he did not try to warn the world of what had happened in Bardos Island (to wit: one of his colleagues had murdered the entire archaeological expedition minus Kabuto after finding an army of ancient Humongous Mecha buried in the underground mazes of the island) and what Dr. Hell was planning (to wit: Take Over the World), opting for shutting himself away to build his super-weapon. Of course, he could have reasonably thought he would become this trope, and decided to not waste his time.
I'm a Humanitarian: The Chip Kamoy in the Gosaku Ota Manga. They were a species of giant, fish-like, maneater humanoids from another dimension that raised herds of humans like cattle. However they had depleted their homeworld's natural resources and were running out of food, so they crossed over to our dimension to find more preys. It can be interesting mentioning one of them declared "humans taste better when they are skinned".
If we're seeing how he actualy fights, both in anime and the manga, Koji is FAR from being a Idiot Hero and is instead more of a Genius Bruiser. He purposefuly gives up only to attack his enemy with the Pilder AND saves the day, and in other moments, he grabbed one of his enemy, and throw it to the other when they attacked resulted in the destruction of said enemy with bare hands. Its a pretty awesome not to mention genius feat on itself. Of course, with Mazinger being such a powerful robot, most of the time his battles consist of direct brute force than planning.
I Don't Think That's Such a Good Idea: When Kouji wants to get in Mazinger for first time, Shiro says that he doesn't think that trying to pilot a super-powerful war machine without previous training is a good idea. Kouji blew him off as being irritating, but Shiro was very, very right.
If It Swims, It Flies: Mazinger-Z got upgraded to be able to swim (in episode 18) and fly (in episode 34). However its mobility and speed gets severely hindered underwater, and its weapons do not work properly, so it may count as a subversion.
Impact Silhouette: It happened sometimes to Boss, either when he was on his own or when he was riding Boss Borot. A particularly hilarious example happened in the Mazinger vs Great General of Darkness feature. His robot flew through a wall leaving a Boss-Borot-shaped hole. It crashed into the battlefield, and it was quickly smashed back by a Mykene War Beast. The robot crashed back in the Institute, leaving a second Boss-Borot-shaped hole right next to the first one (the biggest difference between both holes is the shilouette of the second one was inverted).
Impaled with Extreme Prejudice: In the Mazinger Z versus Devilman feature, Mazinger-Z cut Silene's wings off during one aerial battle. She fell towards the ground below and was impaled through her stomach by the sharp branches of a dry tree. Also, one of the Mechanical Beasts, Toros D7, had a huge metallic spike on the front side to ramming the enemy and impaling it.
Implied Love Interest: Depending on the adaptation, Kouji and Sayaka's relationship varies between Official Couple and this. Although they were the Trope Codifier by Belligerent Sexual Tension, spent most of the time together and were very close at each other, and after the Final Battle they traveled to America together, they becoming a couple was not shown in pannel. The anime is especially bad about this (making Sayaka's feelings very explicit, but downplaying Kouji's ones and showing him getting pervy about other women), but both manga versions (especially Go Nagai original story) are way more explicit about they wanting to pursue a relationship. They never quite reach the Official Couple status, but most fans take that status for granted. In other continuities, though, they become the Official Couple on panel.
Impossibly Graceful Giant: The Super Robot GenreTrope Maker actually subverted this trope. When the series was animated, Go Nagai reminded the cartoon-makers that Mazinger-Z was a huge, heavy machine, therefore it should look heavy. Hence, Mazinger walked apparently slowly, shaking the ground and making much noise with each footstep, and the robot was frequently seen from below to reinforce just how huge it was... Go Nagai wanting Mazinger-Z to seem heavy was the reason of Jet Scrander was a Mid-Season Upgrade. Go Nagai intended for Mazinger-Z to be able to fly all along, but he feared if Mazinger flew from the beginning, the robot would seem lighter than it really was, so he only gave it wings when it was firmly established Mazinger was heavy.
Improbable Aiming Skills: One of the Dr. Hell's Mechanical Monsters (Jenova M9) can shoot down anything as far as one hundred kilometres away. Baron Ashura decides trying its aim shooting down a passenger plane.
In the Back: In the Gosaku Ota manga continuity, Dragon with an Agenda Archduke Gorgon murdered Big Bad Dr. Hell by stabbing him from behind with one sword when he was distracted. Afterwards he pulled his sword from the body, said "So long, old madman" and left him lying -and bleeding- on the ground, laughing all the way as he left the place.
In-Name-Only: Go Nagai's manga and anime series, God Mazinger has absolutely nothing to do with Mazinger whatsoever. The original concept was intended to be a Mazinger sequel, though.
Indy Ploy: Kouji is able to think strategically and plotting strategies beforehand. However, given his rash, hotheaded nature, he is VERY prone to impulsively leap into a dangerous situation and figuring out along the way how he will walk out of it alive. These twopages of the "Mazinger Z: Relic of Terror" one-shot are a godd example:
Kouji: There's no choice but for me to go and take it back!
Sayaka: But you don't even know what the enemy is...!
Intangibility: Mykene War Beast Dante, which appeared in the "Mazinger-Z vs Great General of Darkness" movie, had that ability. When Kouji fought it, Mazinger's weapons went through its body harmlessly.
Interrupted Suicide: Episode 46 features an example where a villain accidentally interrupts a suicide. A woman was about to jump off a cliff when she overhead Baron Ashura telling that they had planted nukes on the Institute (where she had left her baby shortly after). She got so worried about her son that she forgot about her suicide to try and warn the heroes about the bombs.
Inventional Wisdom: In one of the versions of the story there was one lever on Hell Island that served to launch the island spacewards and detonate it. Dr. Hell used it to try totake Mazinger Z with him when he realized the battle was lost. It happened in Gosaku Ota's manga version.
It Can Think: In Mazinger-Z vs Great General of Darkness, when Kouji faces Mykene'sWar Beasts for first time, he -accostumed to the mindless, silent drones that Dr. Hell used- gets utterly shocked when they begin talking to him. Quickly learns that that is not the only difference with the Mechanical Beasts. They are intelligent, capable to think on their own, devise complex strategies, fight coordinatedly and even lay traps. Oh, and they dragged and dunked Mazinger in the ocean, knowing that his robot's mobility is crap underwater, unlike the aquatic Beast that was waiting for him.
It's All About Me: Dr. Hell wants to rule over the entire world because he got fed up with being insulted, scorned, envied and beaten when he was young, and he wants to purge the world out of idiots and forcing the survivors to kneel before him. Likewise, when he was a college student, he befriended Juzo Kabuto. When he realized the woman he loved was in love with Kenzo, he convinced himself they had pretended to be his friends and were planning to backstab him later. The resultwas... not pretty.
It's All My Fault: If you are a character of the Mazinger franchise, it's dangerous being impossibly willful and Too Dumb to Live, as well as not listen to good advice and thinking before acting:
It happened to Yuri -Sayaka's cousin- after she wheeled herself out of Kouji's house in spite of everybody telling her it was dangerous outside due to Mazinger-Z and a Mechanical Beast duking it out. She was kidnapped by several Iron Masks and Baron Ashura used her like a hostage. She blamed herself, thinking if she would not have been so stubborn and would have listened to what people told, Kouji would be safe.
Tetsuya Tsurugi blames himself for his and Jun's adoptive father's death. Given that Kenzo pulled a Heroic Sacrifice to save Tetsuya's life, and Tetsuya was in danger because he behaved like an arrogant and jealous idiot, he is right. During a hospital scene, as he was rambling My God, What Have I Done?, Jun listened in silence, trying to be supportive, but she was not gainsaying him. That might suggest she did not want him grieving, but she did not disagree.
Duke Fleed blamed himself for having been unable to protect his planet and save his people from the Vegan Alien Invasion, and having run away. Actually the main reason he wages war against the Vegans despite the fact he hates fighting is that he does not want the same thing that happened to his homeworld happening to Earth, and he would not bear to run cowardly again. Nevertheless, unlike other instances of this trope he is wrong on blaming himself since he could have not done anything back then (other than dying, that is).
Shin Mazinger Zero: In the first timeline we see, Mazinger-Z has become an Eldritch Abomination. Earth is now a flaming, barren, lifeless rock, and humanity has been wiped out. Kouji blames himself for it, uttering that same exact sentence and stating if he had not Refused The Call and piloted Mazinger-Z, none of this would have happened.
It's Personal: Dr. Hell had Kouji's grandfather assassinated (and Rumi, the maid took care of him and his little brother as his grandfather -and father- were away). As revenge this is not his only motivation to want to stop Hell, but it is definitely an important factor.