Grand Valley Identifiers

The Farm Identifiers are a standard procedure for all children from the Grand Valley orphanages. Similar to the Numbering system used in Grace Field House, they are likely marked before they reach the farm. However, while the Grace Field House orphans' identifiers are on their necks, the Grand Valley children marks are across the chest. Mamas and Sisters, like any other adult human in the Hierarchy of the demons, presumably also have a numbering.

Understanding
The Grand Valley Identifiers consist of a single letter followed by a Roman numeral, then a sequence of 3 numbers, a dash, and a second 3 number sequence. It is so far not known how the identifiers can be decoded. If it is assumed that, like Grace Field House, there are 30 children born each year, then there should be around 30 identification sequences in between those born a year apart, such as those of Zack and Sonya.