He hasn’t admitted it directly, but there is a large amount of circumstantial evidence. Asahi exclusively uses Marcan’s private infrastructure. They both name their systems after little girls from the anime “PreCure”. They are NEVER talking/streaming at the same moment, even when they appear together. In fact Marcan used to stream quite a bit on his personal channel, but once Asahi appeared he stopped almost entirely. They even have similar typing styles once you start comparing their long-form writings. Not to mention the fact that Asahi’s specialities just so happen to align with Hector’s to the point where they can interchangeably work on reverse engineering Apple Silicon. How many people in the world exist that can do that? And how many would share the exact same interests and peculiarities as Hector?

Finally, and my personal favorite: Asahi’s VTuber reveal was by “hacking” and hijacking one of Marcan’s streams. The introduction was literally replacing Hector.

The fact that the comment you replied to is buried shows that it's probably too close to be true and makes people uncomfortable. Are we supposed to believe the character is literally an animated humanoid with animal ears? Is it not ok to question who the human entity behind it is? In any case, it's super easy to spot when it's a man pretending to be a woman, in case that's the source of the controversy.