While I've first learnt about the Deboth and Torin, I was pretty pessimistic ; a mentor looking like a Thanksgiving meal, and all villains were suit villains. However, the Deboth turned out to be a pretty interesting group, notably because of their differences; the turning point however was the reveal that Torin (who had already surprised me since his Seiyuu was able to make me take him more seriously) was himself a former member of the Deboth army ( and Chaos's own brother), who rebelled against the destructive aims of his group. Besides, the second half of the show revealed very different fates for the members of the Deboth army, with different levels of redemption, and fates which were pretty fitting of their deep nature.
Let's start to analyse each major member of the Deboth army
1) Deboth
The leader of the Deboth army, he's an entity which aims to destroy life. The irony is that his appearance changes by taking characteristics of the very creatures he destroys : at the beginning of Kyoryuger, Deboth's appearance is a mix of the dinosaurs and the bugs he previously destroyed, while, at the end, while filling itself with human emotions, he evolved into abeing with an human appearance and human intelligence and speech.
2) Chaos and Torin
I'm gonna analyse Chaos and Torin together, because, while they're opponents and fights in opposite sides, both are very similar, and it's pretty fitting that they are brothers. Both Chaos and Torin fight for what they believe is a righteous fight: Chaos fight to destroy life, as a loyal servant of Deboth, and Torin fights to protect life. Chaos believe in his fight because he's loyal to his master and creator, Deboth. Torin fights to protect life, because, as he went to Earth to destroy life, after seeing the dinosaurs, and how impressive and beautiful life was, he wasn't able anymore to destroy life, because he realized that there was something which deserves more his loyalty than his creator Deboth: life itself. As such, he opposed Chaos and tried to protect the dinosaurs : while he failed at preventing the dinosaurs's extinction, he was at least able to freeze Deboth's heart and as such, seal him.
Both Torin and Chaos created warriors to fight for their cause: Chaos created the Deboth knights, and Torin created the Kyoryuger using the spirits of the dinosaurs. Both are the wise leaders of their troops, and good strategists. Both fought against each other for a long time. Both hate his other brother: Chaos because he felt Torin has betrayed his own family (and the most significant symbol is Torin cutting his brother's wing), Torin, because he hates Chaos's will to destroy life. That said, both aknowledge their link as brothers, even if they're bitter enemies, and Mad Torin is certainly the brother Chaos wished Torin was.
However, there is a key difference between the two, and it's that difference that made Torin win and Chaos be defeated : Torin, despite starting himslef as a traitor to Deboth, cares a lot about trust and wants more than anything to trust his partners. Torin showed plenty of times how much he trusts his Kyoryuger friends, how he cares for their trust. In fact, one of his happiest moments of his life was when he realized that, despite his past as a Deboth, the Kyoryuger still trusted him. Torin's biggest pain is whenever he seems he has failed to be worthy of the trust of his partners, like when he failed at preventing Utchy to be possessed by Dogold, or how he wasn't able to become Bragigas's partner and avoid his death when Gadoma attacked. But, despite the pains, Torin still wants to trust, and in fact, the key part of the Kyoryuger's victory came because the Kyoryuger chose to trust an enemy.
Chaos, because he's been scarred by Torin's betrayal, is scared more than anything to have anyone of his followers betray him like Torin. As long as he feels that his Deboth knights are trustworthy and commited to the fight, he's not afraid, and is even a good leader appreciated by his troops. However, as soon as he fears betrayal, his first reaction is to have the potential traitor either killed if he/she is not useful anymore, like Candelira, or forced into submission if he/she may still be useful, as Dogold. Ironically, Chaos is defeated precisely because of the very generals he threw away, even if they were still loyal when he did this. Because he feared too much betrayal, he ended up betrayed by those who were the most loyal to him : Candelira and Luckyuro.
Last point : it's fitting that Torin and Chaos died the same way: willingly killed by Dantetsu in order to fight in the Deboth hell ; in a big irony, Chaos's last fight was to protect, and Torin's was to destroy. However, Torin won because his trust was the proof of real bravery, while Chaos instead showed fear. After all, the bravest thing to do is to trust others, since it's not easy, and there is always the big risk of betrayal and the pain that comes with it.
3) Dogold
Dogold is the knight of Anger, and he thrives on the anger of others. Anger is an evil feeling, because it induces agressivity, violence and destruction, and, as a result suffering. When someone is angry, he will never cares for the suffering of others. Fittingly, Dogold stays evil all his life and is a violent warrior. However, unlike hate, anger has at its basis a suffering, and it's that pain which creates that violence. Indeed, Dogold is a living armor, with no real body, and he's forced to take over other creatures's bodies to have a full body, and his whole life is based on stealing other living being's lives. Dogold hates himself for being such a wretched creature. However, his parasitic nature also makes him a pretty cunning one, and, despite being prone to anger, he's able to conceal his intents, deceive allies and enemies, and plot against them, as seen with the way he took over Endolf's body, and how he knew how to mimick loyalty after his plot against Chaos failed and Endolf came back, in order to stay alive while waiting the fitting opportunity for revenge.
Anger is also associated with pride and Dogold is very proud ; as such, he hates Endolf for reminding him of his pitiful status as an armor, and how he never fails to humiliate him. His final act was to ally one last time with his bitter enemy Utsusemimaru to take down Endolf, because while utchy was his enemy, at least he aknowledge Dogold's pride, while Endolf took pleasure to humiliate him. At the end, Dogold died an honorable death, the death of a worthy warrior, the only thing Dogold could be proud to be.
4) Aigalon
Aigalon is the warrior of sorrow. Since he's meant to create sorrow inside humans's heart, he's also an evil creature. However, unlike Dogold, he's also very sensitive, since sadness is a deep feeling, coming from the heart. It's significant that his most notable evil act was to kill Ian's friend, and cause Ian a very deep sorrow. However, while he enjoys create sorrow to others, he hates feeling himself sorrow, and when he thought the Kyoryuger had killed his comrades, Chaos, Deboth and Dogold, his sorrow was so big it turned into bling rage, and he tried to kill the Kyoryuger by blowing himself up. As a result, he died a first time, only to be brought to life by Chaos.
However, Aigalon had one bright side in his life : his love for Candelira, who as the knight of Joy, was pretty much his opposite. Aigalon obviously felt that Candelira's joy was complementary of his own sorrow, and became close to her, hoping to feel better thanks to the happiness that radiated through her. Therefore, when Chaos decided to get rid of Candelira, he couldn't stand it and decided to defect from Deboth, only to become a fugitive and a target. Despite that, he wanted most of all to protect Candelira, because losing her would be the ultimate sadness for her. It's because that sadness was associated by the loss of another life he cared for that he realizes his cruelty in killing humans.
He ended up sacrificing his life to save Candelira, choosing to die rather than suffer the horrible sorrow of losing her. Ironically, he was killed by another Knight of sorrow, Icerondo, who wanted to bring him the deepest sorrow. While Ian hated Aigalon, he couldn't help but be deeply moved by Aigalon's sacrifice, and instead of hate, he ended up feeling sad for his enemy. Aigalon himself recognized the beauty of that sadness. Aigalon was ironically avenged by Ian thanks to the powerful sorrow he felt and which was tranferred in his axe.
4) Candelira
The Knight of joy, her whole life is aimed at create happiness and make humans feel happy. As such, her whole nature is at odds with the evilness of the Deboth army's destruction. However, Candelira saw herself as a Deboth, and while her plans involved making people feel happy, she first wanted to have her companions feel happy as well, by being a useful knight. Her plans to get happiness from people could be as harmless as making sweet cakes, or as twisted as making people's wishes true at the cost of their lives. But Candelira only cared for immediate joy, and she didn't really care for stuff as deep as choosing good or evil.
However, one day, she was protected by one of her sworn enemies, Kyoryublue. While she was already amused by the puns of his enemy, she was deeply moved by him protecting her, especially since he knew about her. Moreover, when she met her enemy and fully expected to fight him, he decided instead to beg her to stop her evil plan, and decided to trust her. Nossan even protected her from the wrath of her sister, and he was the one to show her that they didn't need to be enemies because, as the one who brings joy, she could be able to live peacefully with humans while being herself Deeply moved by those beautiful feelings, Candelira sabotaged her own evil plan, and since then, stopped actively fighting the Kyoryuger, only being still wih the Deboth out of loyalty. However, once Chaos started plotting to kill her, and she realized that she received betrayal and pain from her allies and mercy and comfort from her enemies, she decided that the Kyoryuger were more worthy of her loyalty and helped them in the final fight against Chaos. At the end, she decided to work to make humans feel happy with Luckyuro.
5) Luckyuro
Luckyuro is the kid of the Deboth army and the Fun spy. As a kid, he cares about two things : having fun, and being praised by his elders, especially Chaos. Because of his desire to be praised, he's been a very loyal servant to Chaos and the knights, especially his immediate superior, Candelira. But at the same time, he loves having fun, and more often than not, as a typical kid, fun comes before duty in his mind. Luckyuro found plenty of fun in stuff created by humans, like games, puzzles, and especially a shoujo manga, Love Touch. However, he's also pretty smart, and was the first to see how unhealthy Endolf was.
When Amy told him that if he continued working for Deboth to destroy the world, he would lose all the fun stuff he got thanks by the human world, he started doubting the Deboth mission, stopping actively fighting the Kyoryuger at the same time as Candelira. But of course, the last straw was being fired by Chaos, and then, seeing Aigalon and Candelira hunted by their own kind. At that time, he had no reason anymore to care for the praise of the Deboth, and allied with the Kyoryuger together with Candelira. After Deboth's defeat, he joined Candelira in her mission to make humans happy, since, as the warrior of fun, he's deeply associated with happiness.
6) Endolf
Endolf is the Knight of hate, or resentment, created by Chaos because he felt hate was the perfect weapon to fight bravery. Indeed, hate is one of themost powerful evil thought, and Endolf is the evilest of the Deboth knights. Endolf thrives in hate, and he wants more than anything to see others feel hate. He's even ready to have enemies harming them to hate them even more. Unlike Dogold's anger, Endolf's hate doesn't come from an internal pain, but more of a deep desire and great pleasure to hate others, and be hated, in other to destroy his enemies. Hate is cold blooded resentment, the ability to desire harm to others only for the sake of it. Endolf speaks very softly, almost never shows anger, rather enjoying other feeling anger. His aura is even able to increase the evilness in his comrades : because he wanted to be Endolf's partner, Aigalon decided to use in purpose the fact he killed Ian's pal to torment Kyoryublack even more. And Candelira, in order to please Endolf, sang the evil melody which would make Torin turn evil again. However, Endolf wasn't just content to be hated by his enemies. He even took bigger pleasure to torment Dogold, reminding of his nature as an armor, and was even more amused to use his pain device to force him to be his servant. Even when Dogold took control of his body, he only used that time in Dogold's control to increase his hate and managed to expell the lion looking armor more powerful than ever. However, because he was too amused by seeing Dogold suffer, Endolf didn't realize that Dogold would hate him so much that he would be ready to ally with his bitter enemy Utsusemimaru and even lose his life, if it allowed him to get his revenge on him. Endolf died, stunned to see that Dogold's hate would be bigger than his.
7) Icerondo and Killborero
As the new Knights of sorrow and Joy, they are proof of the desire of Chaos to have loyal servants, who would replace the ones who might betray him.
While Riku Sanjo didn't always avoid some inconsistencies in the writing of the Deboth generals (notably Aigalon and Candelira), he managed to create a very interesting group with the Deboth. Indeed, not only did they show very different personalities because of the emotion which are associated with them, he also showed that being a Deboth wasn't necessary being evil, because as long as a member of Deboth started to feel empathy with other living being (like Torin, and later, Luckyuro, Candelira and even Aigalon), he had the potential for redemption. Indeed, a big message of Kyoryuger is how important trusting others, and feeling empathy for fellow living being is what makes a living being be good, whatever its origins. As such, Kyoryuger really deserves kudos, and while not being the best sentai series, is still a very good one.