What do you all think of Mori being a Mighty Child, and what does this mean for Gil Dong and the gang going forward?

I was taken aback, but I liked this curveball. It evens the playing field a bit, since both sides now have a powerful force to go against each other. It also makes things more difficult for Gil Dong (:(), which certainly complicates his search for Eorinie and how he handles his dealings with Prince Choong Won, Jeong Hak (Soo Hak), Yeonsangun, and any nobles he may cross or scholar Song. 

I'm also scared for Ga Ryung, not because she is alone, per se, but because Mori knows who she is and her importance to Gil Dong. Plus, I think he may also have a thing for Ga Ryung--which is weird, but perhaps he's the type that likes women who tell him they are not afraid of him. 

I find it interesting that (despite the time where Gil Dong was forced to keep his strength under wraps), Amogae supported his son's strength. The inverse is true with Mori. His father tried to kill him. I think Mori is somewhat stuck in finding a father figure and someone who accepts him, and perhaps he envies Gil Dong--his charismatic nature, his life, his ability to have family (whether that was Amogae, his siblings, or the Hong clan)--and wants that so desperately that he sides against Gil Dong (even now, with HTH dead). Perhaps he feels that eliminating Gil Dong with garner him a family with any one of the people he works for (sadly, that's probably not going to be the case). 

What do you all think? Do you find Mori to be a fascinating character?

Correct. People who use their powers for bad things end up dying. Yet, Gil Dong is on the same road, according to the shaman. Who specifically determines the "goodness" or "badness" of a Mighty Child's actions? I'm sure Mori will suffer a death fate; he's done too many evil deeds already. 

I always figured the eunuch was unique (excuse the pun). He seemed extremely charismatic and persuasive, even in his small conversations with Gil Dong and GongHwa (Nok Soo). 

I hope she is pregnant as well. I want a baby Hong. 
I don't think Mori will hurt Ga Ryung, because then he would've done it already, because he used his group as bait instead, and because the damsel in distress is just too cliché. But that's how the drama starts so who knows.