Doc's face is covered at all times by a black and green plague mask.
Apparel & Accessories
Doc is dressed in a green, full-body robe and hood. They keep their face covered by a plague doctor's mask, and wear gloves. No part of their body is exposed.
Doc is known to have been temporarily allied with Strahd Von Zarovich. The Seven Wonders found their notes in a room within Strahd's lair, and first spoke with Doc using a sending stone found on Strahd's body. Since meeting Doc, Marvey made a loose deal with them, promising to attempt to return Doc's notes to them in exchange for the cipher key to read them. Failure to make good on this deal resulted in Doc leveraging Jeff's family against the party. The party has since ventured to the Mandehanwei Rainforest in order to deliver their notes. Doc gave Himemiya Llue an open ended offer to let her in on their work should she decide to help them with it. Doc's Notes cite a larger patron than Strahd.
Morality & Philosophy
Thus far, Doc appears to lack a sense of ethics. They state that their actions are the result of a pre-determined purpose. When referring to living beings, Doc speaks clinically, describing the death of an elf as a result of their tests as "expiration" and a "failed experiment." Even so, they do not appear to immediately rely on violence or cruelty. Although they leveraged Jeff Humanman's family against the Wonders, they refrained from harming them so long as the party kept their word, and allowed for the detour to explore the Mire Lair.
Speaks in a stilting monotone.