Excellent villains who stand for everything the protagonists do not are a staple of contemporary shonen anime. For instance, the evil Tomura Shigaraki in My Hero Academia wants to destroy hero society and replace it with his own, and for villains like him, exploitation and deception are standard practices. The League of Villains will even employ dark science to produce new life, specifically the various Nomu, for evil purposes.
Fullmetal Alchemist: Brotherhood also features evil anime scientists, with government researchers assembling a homicidal "doll" army of soldiers with one eye to carry out Father's will and bring about a new world order. The Nomu and these doll soldiers serve as a stark illustration of what happens when bold, risk-taking science is misused to produce a perverted imitation of life, all in an effort to end the lives of others.
How Science Gone Wrong Is Represented by the Nomu & FMA's Doll Soldiers
The doll soldiers known as Nomu in My Hero Academia and FMA: Brotherhood share a number of symbolic similarities, including a critique of science. Since science is the study and application of data with experiments to reach conclusions and produce new things in the process, it is ultimately a completely neutral and objective thing in both fiction and reality. Some magic spells or fictional skills are obviously good or evil, such as healing spells that are good and necromancy is almost always evil. However, science is solely concerned with physical reality and the systematic study of it; it is a concrete and entirely impartial way to experience reality and create new possibilities.
MHA's Nomu and FMA's doll soldiers represent the dark side of not science but rather those who use it, with some fantasy elements thrown in, like myriad Quirks and alchemy. Science cannot by itself be good or bad, but its application can, which is what gave rise to the development of the Nomu and doll soldiers. As tools for anyone's will, chemistry, formulas, lab supplies, and the like can be used in any way; anime villains like Dr. Garaki and Amestris claim that scientists infused evil into the science they employed. They could have theoretically grafted Quirks into people who required them for self-defense or discovered novel techniques for saving lives through surgery and body grafts.
The science used to create the Nomu and doll soldiers, however, had the potential to save and enhance many lives, but its developers had no such intentions. The Nomu, the League's semi-disposable Frankenstein-style shock troops, and the Amestrian doll soldiers, which are similar but without Quirks and in larger numbers, were instead the products of researchers who pushed the boundaries of science to create weapons to destroy other lives. Unfortunately for Edward and the professional heroes, that's what happened when Dr. Garaki and the Amestrian researchers used science to unlock the potential of the human body. Science can create almost anything, including lethal weapons and abominations.
How Powerful Cheating Is Represented by the Nomu & FMA Doll Soldiers
The doll soldiers in FMA: Brotherhood and Nomu from MHA are other examples of villains who frequently use dishonest means to quickly rise to power. In addition to how they use their power, heroes and villains differ in how they acquire it. Heroes frequently work diligently and obediently over time to gradually gain strength, as demonstrated by Tanjiro Kamado's two arduous years of preparation for the demon slayer entrance exam or Izuku Midoriya's training with One For All. In the meantime, villains frequently take control right away using strategies that heroes would never approve of, like using perverted science or making deals with stronger, darker forces.
Examples are many, from people getting bitten to become demons in Demon Slayer to Dr. Garaki using his dark science to create the powerful Nomu in a lab or even grafting new Quirks into Tomura Shigaraki, with no training required. FMA: Brotherhood showed the Elric brothers training hard to master alchemy, all while the state researchers used a huge science lab and many Philosopher's Stones to make those doll soldiers, which were fully combat-ready when awakened.
In this way, misapplied science enables anime villains to game the system and amass power with uncharacteristic quickness and accuracy. It wasn't enough for Father and he favored few to simply train a new battalion of elite soldiers; they also used Philosopher's Stones to create those soldiers in a laboratory. The primary League members were supplemented by Dr. Garaki and All For One with monstrous, lab-created Nomu who were stitched together and each given multiple Quirks to instantly become combat-ready warriors, rather than with new recruits who needed training. If the heroes are to defeat these perverted by-products of misapplied science, they must recall their training and push themselves to go Plus Ultra.