And speaking of Clara-sensei, you can find her first appearance in Bitch Trap, which is also in the free section and was translated by this site over a decade ago. However, even though it's tagged with Kon-Kit as the author, it won't show up if you search their name. You have to search the name directly or any of the other tags it uses.

For those who don't know, Kon-Kit's stuff takes place in a shared universe. The two works where the girls first show up are in the free section, the Clara-sensei one where the brother shows up is in the member's section.