Ah, this appears to be the first Ado post on Danbooru featuring the Gingerbread Boy ("しょうがパン坊や")!

Story time!

At some point, Ado did a read-aloud of this little dude's story. It was on some kind of live stream, and her chat insisted she read it a second time.
Here's a clip (untranslated).
Since then the しょうがパン坊や has become something of an inside reference in her fanbase. I've seen him in sketches of her before.

Someone also made a twitter account for him and frequently posted "I'm fast, I'm fast. I'm number one!" ("速いよ、速いよ。ボクが一番さ！", a refrain from the story) in reply to Ado's tweets. He was indeed fast, often getting the first reply. The replies got her attention and she assumed it was a bot, but it replied saying it wasn't. (Without a Twitter account, I can't see the message anymore, but if memory serves, it was: "botじゃないよ。ボクが一番さ！" / "I'm not a bot. I'm number one!") Perhaps no one will ever know the truth. At one point she tweeted in English and he replied in the same (though an obvious machine TL) so if it is a bot, it's a somewhat sophisticated one.