Its an anime short with chibi characters from Kage no Jitsuryokusha(Eminence in Shadow). Honestly the content itself is so-so, pretty cliché if I had to define it using one word. But honestly its pretty decent, it has good humour that matches the original series(That being the manga/light novel). If you like Isekai Quartet and other animated shorts like that you will most likely enjoy this mini series too.
If you choose to watch this series you should probably follow the original content to a certain extent just so you know the characters to a certain extent. This series does contain spoilers for the original series, hence another reason why I recommend to watch/read the canon content.
