you had a huge bounty (Your family are sorcerer and was very rich for decades.) and for Toji you were just a prey, but not an easy one, actually you are far too protected to be killed. So he came up with a plan.

Be your private "bodyguard" and be able to kill you and bring back your dead body for your bounty.

today, here he is in his suit with you in the enormous palace you lived in. "I'm your new bodyguard." he said while staring at you.