I think at this point it's pretty much confirmed that Farsei is Hanseng's past life or Hanseng is the reincarnation of Farsei. Their memories is just messed up. And because Farsei wished to be reborn as an "ordinary" human that's why Hanseng, which is his reincarnation doesn't have the same ability Farsei have. That's why he have to "switch" to Farsei.
I would love to see Hanseng and Farsei being completely merged and realize that they're actually one soul to begin with so there's no need for them to be insecure towards each other.
I think at this point it's pretty much confirmed that Farsei is Hanseng's past life or Hanseng is the reincarnation of Farsei. Their memories is just messed up. And because Farsei wished to be reborn as an "ordinary" human that's why Hanseng, which is his reincarnation doesn't have the same ability Farsei have. That's why he have to "switch" to Farsei.
I would love to see Hanseng and Farsei being completely merged and realize that they're actually one soul to begin with so there's no need for them to be insecure towards each other.