Looking for an old manga

[killzya2fast]

Im looking for a manga that I read in the past and turns out after scouring my follows its not in there T.T
Its about a kid who has dreams of a swordsmen and basically inherits his skill which is a single slash.
He ends up going to a sword academy where he is just below the girl who is first in class.
Uhh some other things that might be related is that he has a sister(?) and a teacher who uses the form of a cat(?) not 100% sure on those but i think they are...

Please help

 

[ARealCoolGuy]

"The Lazy Prince becomes a Genius", there are no chapters on mangadex, but here's its page: https://mangadex.org/title/26c8f00a-3925-4f22-ac21-83145be2b733/the-lazy-lord-masters-the-sword

 

[killzya2fast]

thanks!