Just questions not complaints (loved the movie)

How does he know Bodachs are called Bodachs? There are mythical creatures called Bodachs which have similarities to those in the film, so does Odd name the creatures after this? Or does he somehow know that that's what they actually are?

It is established that once a Bodach knows you can see it, it will kill you. It is revealed later that they have known for some time Odd can see them, but they have been playing a game with him. By the end of the movie, the game is over, so why don't they then kill him?

Bodachs feed on death and those who are close to death. It is established that Bodachs have the power to both kill people and take control of living people. So why don't they just kill people all the time instead of waiting around for them to die in accidents etc?