I'm really excited for the next update.
Is Shen a spawn of Memory btw? Do we know anything there?
I think the main components for Shen's ability is Memory and Dark.
1) Why Memory:
The effects the targets see while in trance, seem to be created through their own experiences. MC sees his mother and the HERO agent is guided by Shen to see whatever he suggests.
2) Why Dark:
I have 2 reasons.
One is that Shen's power "just works". Every target he used it against didn't seem capable of resisting it. Dark is generally associated with suppression effects, and we also have another monster with mental attacks capable of bypassing resistance, the Minyaks, who also derive a small part of their abilities from Dark.
The other is that the apparitions the target sees seem to have substance, but the behavior of the materials don't seem to be correct. So the target thinks about a wooden door, but if he tries to break it, it doesn't behave like wood would. According to Valravn's monster report, Dark "mimics" real things.
3) A possible 3rd component?
There exists a possibility that Shen also has a Authority component, which allows him to "command" the target to fall into trance. MC for example can force memories onto a target, but he can't force the target to behave in a specific way. Shen can "hypnotize" his targets at will. Every time he uses his powers, the effect is the same. The target falls into a trance, he can't perceive anything other than absolute darkness, and eventually the apparitions will take the form of whatever he is supposed to see.