Reili
Rei just created a Unlimitied Blade Works Psion bloodline!!!!!!!!! Also any student he gave full permison to use a specific hiğh level seuence or a god series also founded their own bloodlines Currently there are two confirmed but there is probably more since this two were not the only students Rei liked shown in game trials Rei created the begining of Sequence bloodlines
There's many thing that I want to ask. 1. Why the MC cannot control his eyes? 2. Who or What that judge the use of The Nine Blade as Negative use ? 3. Since killing or hurting people is negative no matter the "reason" is then the "Negative Use" Restriction is contradiction itself unless there's something or someone to judge the "User Intention", maybe there's something like A.I or just some "Parameter" ?
Rei can build his reputation as a professor in First High School for two years. Rei wouldn't treat Tatsuya as a tool like the most of the people affiliated with the Yotsuba house. It would be better that Rei show some actual feeling of care towards his nephew as he teaches him to be somewhat more humane.