First Mentioned: TBFGK Epilogue 17
First Appearance: Hvs.tCF 160
Molls are animated, non-living units created by Dollamancy. They look like moving white marble statues, like rock golems, but knight class. Transylvito Molls are carrying classical spears and shields of burnished metal, and wear togas of linen. They are all carved in the likeness of women, as armored warladies.Erf-b3-p160
Real World References
In the early 20th century, the female companions (sometimes girlfriends, sometimes not) of (Real World) American gangsters were called "molls" or "Gun molls," and the use here as a Transylvitian unit would appear to be a reference to that usage.
A "Moll" is also a derogatory term for a woman in some English speaking countries, like Australia, although this meaning mostly originated the same way as the previous.
You could also read Moll as a portmanteau of marble and doll.