[Kiwami]

The train of thought is interesting, because we know from Geed that Ultraman Hikari made the Ultra Capsules and the Riser. So we should assume he also made the Ultra Medals and the Ultra Z Riser, maybe even as a direct upgrade.

I always wondered what they are made for, but someone raised a very interesting point recently on this forum. I forgot where and when, but the post speculated how it's mainly newer, fairly young Ultraman who use fusion forms, as means to make up for their lack of power an older Ultra would naturally have.

It’s of course not an in-universe explanation as form changing was simply introduced to sell more toys, but I like the idea that older Ultraman don’t need the support of fusion forms.

Tie this together and you actually have a great explanation to why Hikari keeps making all this stuff in the first place: The number of battle-hardened champions like the Ultra Brothers is very low, so in a state of emergency they couldn’t possibly defend the entire universe alone. Cadets need training and experience which in dire situations they have no time to acquire.

Which is where all these items infused with the strength of their very best fighters come in: They’re made so that younger Ultraman can power up and rise to the challenge.

Whoever sent Genegarg and is behind the Devil Splinters purposefully stole these items so that the rampaging monsters could eventually overwhelm the Land of Light.