Apparently, she’s a rival to Raziela the Shroud across various points in space-time. May be a noblewoman of some sort, although she seems very informal, if not crass, most of the time.
According to Ione Hearn, she is a vampire.
Dialogue Theme (casual): Umineko no Naku Koro Ni – Happy Maria! Instrumental
This character was originally just a one-off joke idea. Ha ha, Raziela reminds me of Bern so clearly she needs her own Lambda.
I was somewhat hesitant to ever actually use her, since the humor was largely irrelevant to the players. Over time, though, Tertia’s concept evolved from ‘lol seacats’ to having stronger ties to the existing lore and setting. Eventually, I decided that she was a sufficiently amusing story facilitator to actually let her in. After a few back-room cut-scenes, she set off to find The Party.
She also began to take on some quirks that drew inspiration from a series of other characters who aren’t a 34. Her goggles and means of transit reflect some of those influences.