Quoting a theory from MindMeltonABun on tumblr:
"Taluipa’s Son/Bok Gil = The Imoogi
As previously mentioned, I had theorized that Taluipa’s son, Bok Gil, must have been one hell of a powerful being given that his mom was a powerful Goddess herself. As to what those abilities could have been, it is still a mystery. However, I feel like his powers would’ve been connected the ones Taluipa had (i.e birth, fate, and ability to see what others cannot see). Again, not much was mentioned about him other than he committed suicide and that his name was Bok Gil.
Now let’s look at the Imoogi, we know that he has the power of life (bringing the bird back to life), death (sucking the life out of his nannies), and rebirth (being reborn as that boy).
If you think about it, when Bok Gil committed suicide, his soul/body was neither in the land of the living nor the dead. He was in between those two realms or in limbo. Connecting this to the fact that the Imoogi said he was born in a place between the living and dead, there is a significant possibility that Bok Gil is indeed the Imoogi. Furthermore, if you look at the kinds of power the Imoogi has and the powers that Taluipa has, you will find that they are strangely similar or related. If that doesn’t convince you enough then just compare the voice of Bok Gil to that of the Imoogi!"
THOUGHTS?