Courts of the Crane Clan

Also, "Only the most powerful of entities can survive such an event, either in the utilization of such a scroll or as the target of its effects."

The self-sacrifice I guess I took for granted if it leads to some serious evil being contained.

That bit about the Black Scroll having already been opened (thus allowing Kali-Ma to escape or something), still gives it residual power (even though Kali-Ma is dead)... does the scroll's power rely on the existence of the being it used to contain?

Yes, as far as I understood, the scroll is currently empty.