SPOILER (Take some of these with a grain of salt, I haven't read the novel in so long)
If I remember correctly, his second brother (bless him, he's so sweet) having high affinity with spirits and only talking in the language of spirits, and Mom is an archmage just like the headmaster and at one point tried to erase/manipulate his friend's memories when they visited during winter break. There was also a part in their mansion where there's an ancient artifact that connects to other-dimension(?) and his Mom and eldest brother goes to battle there so the demons and such don't invade their continent or something like that.
Golems are used as gaurds/staff around the estate (his friends are dumbfounded because golems are high maintenance in a way where every actions needed to be coded or something), there are also devils/demons who got into an unfair contract and became slaves for hundreds of years. Again, everything about the Wardenaz family is out of the ordinary but Lee Han couldn't see it because it's normal to him. Might I include what I read that apart from Lee Han who's a teen, everyone in his family are hundreds of years old? All the rumors surrounding their family didn't start in just a few days, it's been the talk of the empire for YEARS, so there's gonna be truth in it.

I'M EFFING CUROUS ABOUT THE WARDENAS FAMILY WHY ARE THE RUMORS ABOUT THEM SO SHADY AND SUS