Despite their mutual love of counting and identical appearance, they both hate each other to the point of wanting the other dead.
Dementia Jastira has a darker attitude when it comes to counting, she prefers to count corpses instead of simply counting the way her counterpart does. She spends most of her time talking to others around town, and, of course, counting. The only time that she breaks her daily routine is when people visit the town.
Like the other residents of Split, Jastira hates her counterpart to the point of murder, but is unwilling to risk ending up on the Hill of Suicides for killing "herself." According to dialogue, she is hoping that someone will come into town and help out by driving the Mania residents out.
After hearing that the two sides dislike each other, the Hero will either be pointed to Dementia Horkvir or Mania Horkvir, depending on who they were talking to. Either way, Horkvir will explain that neither side can stand the other, and that the only way to fix this is by killing their counterparts.