@Angie7 Remember that one guy early on who awoke from a centuries-long meditation (vines grown around him and stuff), only to then vaporize or such because he'd attained the enlightenment he'd sought? His granddaughter (that blonde blue-eyed maiden) now heads the so-called "Demon Church" (which by the way is an exonym, they call themselves the "Church of Enlightenment" or such - you can sorta see here why they use the term "church" rather than "clan", a closer translation could probably be "cult", albeit without the negative connotation) It seems to me that a lot of terms and concepts here that confuse/overwhelm outsiders are probably very common concepts in Korean mythology/folklore and tend to be glossed over for that reason.
Also, the masked troop will likely not try to harm Ga-Jang (if they've been instructed on his identity, that is), seeing as how the scheming bunch (the brat, his dad and the old twins) have their eyes on Ga-Jang and his kids for their own ends, and the "Administrator" seems to have been following the situation quite closely. But then again they may be ignorant and things might play out exactly how you described
PS: Can't blame you for not being able to remember every name, clan and faction in here - those alone are hard to keep track of, let alone the politics between each of them...