Transformation Is a Spectrum
You can see at least 2 types of transformation:
On one hand you got: “The curse twist my body into an unholy mockery of life and reduces me into the base instincts of a beast”
And on the other we got: “Standby, Henshin!”
The first is the classical werewolf curse in any flavour you prefer. It is transformation as a violation. Your body is taken over and corrupted for nefarious reasons. Your own self is consumed and you agency is removed. Most of the horror comes exactly from that. Even if a lot of these stories focus on everything but the transformed.
Henshin in the Kamen rider sense is more self actualization through ritualization. Your self is elevated one way or another and you become more powerful more capable of changing the world around you.
And even if different poles i pose they are not so disparate. The first Kamen rider, Takeshi Hongo was a guy that gets captured by a Nazi adjacent organization and transformed against his will into a wind powered, grasshopper themed cyborg. Only reasons he does not becomes a monster is because he escapes before they brainwash him.
This is a theme across most of Kamen rider from the first one to even the most recent, Zeztz. The idea of the protagonist being forcibly turned into something no longer fully human trough some mechanism and deciding, or being pushed, to become a hero underwrites most of the franchise.
The transformation still has a cost, Hongo knows he is no longer a normal person and routinely mourns not being able to do simple things like comforting a child. And most riders need to navigate their new existence. Part human, part hero and part whatever the current seasons decides the suit to be.
This is surprisingly not an uncommon theme even this side of the pacific either. For example in comics Dr Banner transforms from mild mannered scientist into the brutish Hulk. Benjamin Grimm is turned into the Thing. Both due weird cosmic or nuclear accidents. And of course lets not forget the most interesting case: Peter Parker.
I say this as Spooder Man has always been one of my favorite comic book heroes. Feels less, majestic than stuff like Superman or even Captain America and more grounded than even the Batman despite having literal spider themed superpowers.
He is also closer to Kamen rider as he was at some point a tokusatsu hero too. He even got his own megazord
There is also something different from all of these compared to the average werewolf. For all of them the transformation is a baseline. Only Banner transforms but unlike a werewolf or other cursed being where the trigger is known an expected he is one poorly made Starbucks order away from turning into the Hulk there is always this constant pressure that something may trigger him. Banner knows his baseline is always off as he is always one step away from the Hulk anytime. But for the rest they do not even get a transformation sequence. Grimm is stuck like that, a couple episodes do deal with way to temporarily fix it but he is always The Thing he does not turn into it. Parker and Hongo do not even get the courtesy of a visual marker. Neither can actually detransform fully. Parker cannot stop being spider man and Hongo cannot stop being a cyborg. Parker putting on the costume and Hongo the suit are similar as they are closer to doing whatever Bruce Wayne does when he does the batsuit they do not change their nature as much as cover their identity.
The main difference here is the agency. A werewolf is fully a victim he is in most cases not even there after transforming. But for the heroes the transformation comes with a burden. As Uncle Ben so eloquently put it: “With great power comes great responsibility” all these people saw their situation and, sometimes reluctantly, decided to use it to help others. Peter Parker got handed an indictment in the shape of vocation and it is his problem whatever he decides to do with it. But now every time he chooses not to help is a choice. In the opposite moral sense we have Venom and Carnage. Yeah Brock and Cassidy are only hosts to the symbiont but you could argue they got handed something and decided to use it for their own gain. Evil but the agency is there.
So even in the heroic sense transformation can cost you, overwrite you and place a burden on top. Turning into a hero is not as clean as it seems and neither the opposite. Maybe even the werewolf is not that far off from the henshin, at least in some readings.
Specially in modern interpretations the transformation can read as self discovery. Transformation does not override you as much as reveals you or even forces you to really look at yourself and assert what you really are despite your form changing. That is again similar to Hongo a lot of the first season of Kamen Rider is him going out of his way to assert that despite being a cyborg now he is undeniable Takeshi Hongo, that his self transcends, in a some way, his physicality.
It is a rather novel idea, at least to my knowledge, to use lycanthropy or nahualistic transformation as i prefer to call it as liberation rather than body horror. Nahualistic because it affords any type of transformation and is not limited to wolves. There is also this reading as werewolfhood as liminality. Something that lives in between human and monster and yet is neither. Or maybe it is both monster, human and a bit more than a sum of both. Going back to our superhero analogue this is like Banner and even Parker sitting between two states one more explicitly than the other. Parker in particular is simultaneously spider man and a journalist and perhaps a bit more than those two things combined and a lot of the texture from his stories is him navigating that duality.
And i really like this reading of transformation along with the idea of self-assertion it lets us asks things about identity. Whereas heroic transformations foist a moral burden on you and asks you to deal with it Nahualistic transformation foist a different state on you and ask you how much of you is still there and what was contingent on your shape.
Thus we can tell that transformation is an spectrum. Well that is the wrong word, continuum is the formal term. So It can overlap. Hongo is a bit of both, his transformation was forced upon him and yet he decided to use it to fight Shocker. And he is also doing it as a way to assert he is still unmistakably Takeshi Hongo despite being a cyborg.
In other words there are 2 types of transformation in media: The nahualistic curse and the heroic henshin and both exist on a continuum with werewolves on one end and super sentai on the other. And the most interesting version are those around the middle that do a bit of both as they can carry themes of self assertion and vocation.