I think we're all going to have to start wondering why reincarnated characters seem to end up so incredibly overpowered. Slime works through its general laid back tone and charm but there isn't a lot more to it.
That Time I Got Reincarnated as a Slime Episode 24 (Extra) Review - Want to know more about Shizue and her exploits before meeting Rimuru? The answer to that is definitely yes.
The 12 Days of Anime Characters turns to a character who only had a few episodes to make an impression, but boy did she make an impression. We're looking today at Shizue from That Time I Got Reincarnated as a Slime.