Hey, I forgot to mark which chapter I was at... i know that it was after some crown prince tried to set a trap for the mc and his sister/ cousin (idk anymore) and used their clan members as bait greets Toastbrot
If I remember correctly, his clan is only mentioned in the beginning of the novel, so look at the first 100 chapters or just start from the beginning again
After he join academy he see his sister in chariot when he walking in the capital street. Then he join party in the castle in disgus( he disgus him self as princess's body guard) to talk whit his sister. But all of them trap they use their father as a bait then trying to kill them. ı say look around 250