u/AsiaBella

The title is a bit clickbait because I don't think she actually sabotaged it, but bare with me a sec.

I was rereading the manga recently and a question came to mind: How is it possible that Hermit always helps Weisz build his suit technical and IT side, yet Arsenal always ends up draining too much ether gear from him to the point he can't use for a bit after a fight?

The same Hermit who (albeit unwittingly) managed to create a rector who wiped out a planet >!and create a Goddess through overdrive!<? Is it possible that she can't make something as "simple" as a superhero suit? Or at least correct it after the first use in fight? The same girl who knows much more than Weisz about the technical aspects of Arsenal as shown multiple times in the series? Somenthing doesn't add up.

And here comes my in-world theory: Hermit purposely nerfed Arsenal to prevent Weisz from getting hurt.

Knowing that Weisz was not an expert in these things yet but was acting by feeling on everything, there was a greater risk that he would get hurt with a weapon like that at its fullest power. And after what she's been through in her past, I don't think she wants one of her creation to hurt anyone again, so it was "better" for it to put its user in "a timeout" for a bit of time after one use by draining almost all his ether (Which is also convinient to the plot lol)

To confirm my thesis, there is the prototype of the U0 where Weisz himself says "I can't get it to its full potential without Hermit" a sign that he himself knows something or realized it while recreating the suit.

There could also be the possibility that she did it to "spend more time with him" and rebuild it each time, but seeing Hermit's character it's more likely that she did it to make him happy with the suit, yes, but in a safe way. This also explains why the suit, although customizable, gains power "slowly" over the course of the series. The more Weisz gets used to using it, the more Hermit "de-nerf" it.

So that's my take, let me know what you think in the comments :)