Larta magus
Larta Magi are non-Gifted members of House Jerbiton. They were introduced in the Houses of Hermes sourcebook and were further discussed in the Fourth Edition Sanctuary of Ice:The Greater Alpine Tribunal book, but are notably missing from the Jerbiton treatment in Fifth Edition's Houses of Hermes: Societates.
Guardians of the Forests contains an obscure reference to unGifted members of House Jerbiton (page 111). This is probably meant to refer to Larta magi, but is likely an oversight and not intended to establish their existence under Fifth Edition.