A whole cadre of ninjas and secret police scour the land, plying their unholy trade

One thing's for sure. The Daimyo of the Shimazu clan will not see heaven. 

My current Shogun 2 campaign is going terrifically well, my armies conquering their way across the land. In my first decent playthrough of the game (I got mauled at previous attempts, the AI is much improved in this new Total war), I've learned the value of alliances which can be vital if you want someone to watch your back when Realm Divide hits, where everyone else gangs up to kick your overpowering ass. Okay, the Takeda and Date got thrashed so maybe weren't the best allies, but I had the right idea.

Secondly, I'm making use of agents. A whole cadre of ninjas and secret police scour the land, plying their unholy trade. This is why my Daimyo will not see heaven. In the course of about 30 years, he's ordered countless assassinations and underhanded tasks. I've lost count of how many people I assassinated, and whole towns and armies have been bought over with Shimazu gold. Is it wrong to kill a monk? Two monks? Three? Four? How many more serene, wise and religious men must I kill?

Very powerful, these agents. Perhaps a a bit too powerful.