t0raa is probablly Whoopsatro's alt Twitter account for NSFW material. In addition to drawing the same original characters, the juxtaposition of pixelated and non-pixelated elements is too distinctive a style. But I couldn't find anything definitive.

That's where I was at too, but this tweet:

atroさんのキャラクターを描くのは辞めようかな。

which google translates as

I wonder if I should quit drawing atro's character.

suggests that the two are distinct individuals.

Okay, I found something definitive. This image actually appears in this patreon reward along with other images posted to t0raa's account. So it does seem clear that whoopsatro is the author of these images, and since basically everything t0raa has posted follows that it's reasonable to think they're the same person.