Split symmetry syndrome

The split symmetry syndrome is a birth defect that causes the affected newborn to be literally split in half partially and be mirrored horizontally. Normally non-pair organs can be duplicated this way too, like the heart. People with this syndrome can be quickly recognized due to a symmetrical ridge stretching across their entire body.

Only known people to have this condition are Nkaanmykiunsuns and Vuisul. It doesn't seem to affect them negatively, but there are supposedly worse cases of newborn babies whose splitting is more severe and possibly fatal. It is unknown if the two mentioned people were at risk during birth and whether or not (and how) the split changed during growing up.

It is also currently unknown what causes it or if interspecies breeding increases the possibility of it happening. Nkaanmykiunsuns's origins are unknown and Vuisul is known to be a hybrid with a more troubling condition on top.