Time for a double proposal, yaaay, and this time for a comic that got me into the franchise of Godzilla after so long, let's start with this, yeees!
What's the work?
The trilogy of comics known as Godzilla made by IDW Comics, follows story of the pretty famous Kaiju in a new continuity which forms the comics of "Godzilla: Kingdom of Monsters", "Godzilla Ongoing" and "Godzilla: Rulers of Earth". The first one starts with the first appearences of the kaijus, with them being seen as threats to humanity and them fighting each other. The next one we get the appearence of even worse news, as Space Kaijus get to Earth, revealing to be even worse than the one on Earth, so now humans have to somewhat ally with the Kaijus as they don't go to kill humans just because, while also our protagonists being Kaiju Hunters. And by the next one we have the first protagonist coming back, now having to face more Kaijus, Godzilla fighting more, and two species launching a big attack against humanity by using their Kaijus.
For this proposal, we are going to focus in the worst of the Kaijus and the worst of one of the species controlling Kaijus... This is Gigan the giant lizard cyborg and the Emperor of the alien species of the Cryogs.
Who is Gigan? And what did he do?
Appearing for the first time with the Space Kaijus in the second comic, Gigan would end up going against causing as much deaths as he could, fighting off Rodan in an effort to take over the planet and wipe out anyone against them. After causing a bunch of deaths and destruction across Hong Kong, using his buzzsaws for it, Gigan would end up finally defeated after getting blinded by Rodan, who he also attempted to cut off his wings at the beggining of their fight.
Coming back in Rulers of the Earth, Gigan would fight Kumonga, faking his death to cut off one of its legs and then burn the whole valley. Getting rescued by the Cryogs to make him even more powerful, Gigan would be unleashed next to Orga on Area 51 and Las Vegas, once again focusing his attacks on any bystander he saw, all to show off his sadism. Fighting against Godzilla and even attacking Orga in the process as he became unstable, Gigan would refuse to stop the fight for his love of it (against the orders of the Cryogs), until finally being knock out by Godzilla and Jet Jaguar and transported away by the Cryogs.
Becoming even stronger, Gigan would defend the Cryogs against his former partner Spacegodzilla, making him fall onto Earth. Being freed once again, Gigan would decide to destroy all the fleet of the Cryogs by himself, having no regard for his former boss, just wanting to continue with his rampage (which his former boss used to defeat the Emperor, who ended up being killed by Gigan). At the end, Gigan fought against Jet Jaguar and was defeated, although the ending revealed that he was still alive and getting more upgrades in a completely mysterious place.
Who is Emperor Karkaro? And what did he do?
Emperor Karkaro was the leader of the Cryogs, who reveals to be the worst of his species, even against the member that we saw the most in the comics, Admiral Rhizon.
Although supposedly a hero of their race, its revealed by Rhizon that some time ago their planet was attacked by the powerful King Ghidorah and while their people were dying, the Emperor just left them to die, making no effort on protecting them and just escaping as the true coward that he is.
As it is revealed, Rhizon was only wanting to take over Earth to use the many Kaijus that live in there to fight against Karkaro, efforts that ended up being useless thanks to the humans and the kaijus themselves. Making his appearence with a big fleet, Karkaro took over Rhizon's ship and locked him in a cell, while also killing everyone aboard Rhizon's ship. Deciding that end all of this once and for all, Karako sent multiple kaiju beings known as the Trilopods to completely wipe out the Kaijus and humans on Earth, all to make Rhizon watch as all of his efforts to defeat him were useless against him. Nearly winning thanks to the Trilopods abilities to copy the abilities of the other Kaijus, thanks to a big team-up of Kaijus, even some that were previously sleeping to defeat the big power of the Triplods. As well, Rhizon would get Gigan unleashed to get Karkaro's fleet to be destroyed by the powerful kaiju.
Falling onto Earth, Rhizon would use his chance to grab Karkaro and use him as a human shield against his troops, to then finally end his life by throwing him against one of the attacks of Gigan, avenging his people finally.
Mitigating Factors
Nah, neither of them have anything close. Gigan is constantly shown to just be a sadist that loves to kill as much people as he can, focusing his efforts on doing that and even going against orders just to continue killing people and fighting, even being called "evil", with none of the other kaijus showing to be like this.
Meanwhile Karkaro is just shown to care about himself and no one else, being a coward that left his people to die to save his own skin, while also showing no respect for humanity and just wanting to make people suffer to continue his conquest and show his power. Even Rhizon, who is no good either, shows standard against his horrible actions and cowardly, even showing respect for the Kaijus and the humans by the end, while also being the one who saved some of his people in Ghidorah's attack, showing that not everyone is as bad as the Emperor.
Heinous Standard
I say they both pass pretty well.
Gigan goes around causing death and destruction across the cities of Hong Kong and Las Vegas, aiming agaisnt the people to get even more people, tried to mutilate Rodan's wings, wanted to wipe out everyone on Earth to take over, aided the Cryogs in their own attempts of wiping out humanity and even killed dozens if not hundreds of Cryogs in their fleet for his own sadistic fascination. With no Kaiju going into causing pain as much as he did, not even Spacegodzilla or others, with Gigan being portrayed as the worst for his sadism.
Meanwhile Karkaro, who has more resouces than Gigan, left millions of people to die against Ghidorah, showing no care for them, killed off all the Cryogs in Rhizon's ship just to make him suffer and even attempted to wipe out all life in Earth including the Kaijus, going even further than Rhizon in this attempt.
Final Verdict
I will say yes for both the sadistic mass murderer that is Gigan and the cowardly conqueror that is the Emperor Karkaro.