This hatchling appears to be... dead?

Perhaps not. It seems to be active during the night.

Young dragons are relatively defenseless. They are born with relatively soft scales, which are shed and replaced with harder ones as the hatchling matures. Once a hatchling’s wings grow in, it typically marks the beginning of maturation. At this point they are often capable of hunting on their own and are usually left alone by their mother.

Shiwa may be small, but she's as tough as nails. She had to become so, in order to survive: she was the only Undead hatchling in Ysaedda's cave for a long time, and the adults were not always around to protect her, though they did their utmost. As a consequence, Shiwa learned not to try to befriend the living, as this always leads to hostility, and lived a lonely life for a long time. Moreover, Maraeva's warmongering influence added fuel to flames of Shiwa's dislike of those who enjoyed the pleasures of normality. However, Nishise's arrival in the cave has somewhat calmed Shiwa, who found in him the playmate she had always yearned for.