Hmmm... if I ever do a sequel to "There's Always a Way", I can have Riley get hired as a Post-War DADA teacher by Minerva...
His first act will be to change the course name to "Advanced Conflict Resolution and Agressive Negotiating Tactics"
I can see him using the assassination of Fudge as a case study for the seventh year class, and setting up a school-wide game of
Assassin running all year long. The Slytherins would either love him or hate him, depending on how much they find out about his past. The Gryffs would be horrified at first, but some might catch on that he's a
really good friend of their most famous recent alumnus. The Ravenclaws might be able to appreciate his teaching (MIT&T is a pretty serious school after all), but be dismayed that every single damn Assassin tournament is won by Luna Lovegood (who was badly injured and didn't return for her seventh year until now).
Hufflepuff is driven to the brink of insanity, and only leaves their common room in large, heavily-armed groups. He really should have offered to grade them on a curve.