The Mystery of Intermediate Mass Black Hole?

Theoretically, they're possible, but you just don't see them. The question then is to know, how did it get made? How did you form a black hole out there in the middle of space with nothing around you? Usually black holes are made from stuff, and then ther's other stuff around that didn't get black holfied,. And so i guess maybe, daniel, let's talk about how you would even define an intermediate Black Hole.