The Great evil must be Charles Choi's 2nd Body. As Jinyoung Park said Charles Choi is not dead even tho he and we saw how he died.
I'm suspecting too that the Quest System is James Lee cause he's the only one who's power so strong yet with unknown origin. He could be using the System like Kim Soohyun. The Quest System said too that he was also a chosen one before like Kim Soohyun so probably the Previous Quest System must be from Gen 0 then pass it to Gen 1 then to Kim Soohyun.
Previous Quest System = Gen 0 (Unknown)
Current Quest System = Gen 1 (Possibly James Lee)
Current Chosen 1 = Gen 2.5 (Kim Soohyun)
I'm suspecting too that the Quest System is James Lee cause he's the only one who's power so strong yet with unknown origin. He could be using the System like Kim Soohyun. The Quest System said too that he was also a chosen one before like Kim Soohyun so probably the Previous Quest System must be from Gen 0 then pass it to Gen 1 then to Kim Soohyun.
Previous Quest System = Gen 0 (Unknown)
Current Quest System = Gen 1 (Possibly James Lee)
Current Chosen 1 = Gen 2.5 (Kim Soohyun)