Recruiting his former students.
U see.. when these psykers have all the fame and reward... they can get away with all the shitty deeds they do behind the scene.
Villains are basically genetically wired for doing evil shit and society sees them as solely bad guys. There are some who can resist this corruption but most usually give in to their desires (like those which addiction issues, they need the violence) and continue society's bad impression of Villains only being evil.
Psykers are seen to be genetically wired to do good and thus be Heroes, this is wrong. They aren't corrupted from the get go like Villains but they can choose to do evil. But society doesn't really see it.
What we have is a situation ripe for abuse.
Which is what Cassian found out right before he was murdered.
Part of his revenge is to expose this corruption, change society's views on Villains, and protect his loved ones.
Which is why he is recruiting his former students and possibly more Pyskers.
But this will take a while because it requires society to see they persecuted innocent people because they were different and that is extremely hard to do because it means they need to admit they were wrong and did evil to them in good's name because they were bigoted ignorant idiots.
What is he doing rn ? I swear in this book the heroes (psykers) are the one to pick a fight with villains .. makes me wonder who’s the true bad guy