So if the question sounded a bit confusing, allow me to explain.
In media that feature a lot of non-human characters, such as many video games, anime, manga, or movies, the low-level enemies always tend to look blatantly non-human, ie generic monster.
However, as you encounter more enemies, you start to notice that the more powerful the enemy, the more human they look. They might still retain some monstrous features, such as horns, tentacles, claws, etc, but their overall figure is very clearly humanoid.
Let me use some examples to illustrate this observation.
Dragon Ball: Cell has various forms that he transforms into. However, his most powerful form looks the most human.
One Punch Man: The final villain of the first anime season is Boros, an extraterrestrial. Most of his subordinates look very alien-like, such as Geryuganshoop, with the big eyes and tentacles. However, Boros himself looks very human-like, save for the single eye. His hands even have 5 fingers.
Gantz: In the Osaka Arc, the final villain was an alien called Nurarihyon, who just looks like an old man.. His human-like appearance even caused some of the characters to doubt his status. However, his two subordinates look viciously demon-like, and all the other lower-ranked aliens also look very monstrous. Nurarihyon is the strongest of them all, but resembles a human the most. Also, in the final arc, the final alien antagonists are almost identical to humans in appearance, behavior, and civilization. They serve as the final villains since they're the most powerful aliens our humans characters have had to face.
Bleach: The Hollows all look like your average monsters, and are usually not that strong. However, the Arrancar, which are basically Hollows that have ascended and gained new powers, all look like humans, save for a few features. The Arrancar are exponentially stronger than regular Hollows, and serve as the antagonists for a major story arc.
There's a lot more series that implement this trope, and it extends far beyond just anime and manga. I'm just curious as to the reasoning behind it.
Is there some kind of physics-based reason for why stronger enemies tend to be humanoid? Is the humanoid form factor the most optimal one for combat?
Or is this some kind of literary technique that I'm not familiar with? Clearly these creators all have this type of design philosophy in common.