I've been thinking about that as well.
Perhaps something along the lines of reading a feed from the Mangadex API
However, although I'd like the "Manga" magazine to grow, I do feel like I'm a bit stuck in the Reddit mindset.
Part of the appeal of being a "Federated" instance is that you can get content from anywhere, regardless what instance is the origin.
So, it shouldn't matter if I go to the manga "magazine" or get the feed from elsewhere.
This is very much at odds with how I previously consumed content though.
Unlike Twitter where you follow a hashtag, Reddit taught me I should go to sub-communities if I want to follow discussion.
So should we just neglect magazines and simply comment under individual posts found under a #hashstag or drag Reddit's style of browsing into Fediverse?
In any case, as far as I know the Kbin API doesn't yet support a bot that'd post like that.
You could, however, simply make a bot that uses the UI (using JS to fill out fields) to post things.
It'd break the moment it faces something like Cloudflare or any other anti-bot measure, though.