He cut/filed them so he doesn’t hurt MC
In an earlier chapter the one of the twins points out Jaeshin’s hand, so I think it’s referencing that one hand has his long nails and one hand has short nails. And he probably did this for Nok.
he actually got his nails cut in ch. 24 since lee nok complained that it hurt every time he fingered himヾ(☆▽☆)
I think it was in chapter 22 when Jaeshin goes to hear Nok's answer. He's sure he'll agree so he bought the oil and made a great SCREEECH on the wall with his nails blunting them. Because every time he used them Nok was groaning that it hurts.
Is one of jaeshin’s hands fingernails short and the other long cause he’s half human or is it because he doesn’t wanna hurt our MC(๑•ㅂ•)و✧(๑•ㅂ•)و✧