Alright,
from this point onwards, you are to call me "Otou-sama".

Yes, Otou-sama

I have taken you into my care to raise you as my successor.

This is in order to maintain my family's lineage as high-ranking sorcerers in the Society of Magicians.

I have no need of those whom I cannot make use of here.

Do I make myself clear?

Yes, Otou-sama