Tarkin is the current Grand Moth of the nameless mothpony village found in Dust Valley, a modest but well-kept settlement along the central caravan route which stretches through the mothlands. After his caravan broke down, he and his party gradually established a permanent community at the location. Tarkin has guided its development hence. It now serves as a place for traders to rest and resupply. 
As time has gone on, he's taken the role of the village archivist; keeping and maintaining the closest thing the village has to a library, ensuring that the written history of the town is preserved, as well as passing on his knowledge to anyone who comes asking. He is protective of his chronicles and has become mildly paranoid that everyone in the village is out to get his scrolls as many a hungry, absent-minded moth has been known to idly eat paper or fabric before thinking of what they're chewing.
Nowadays, Tarkin leads a quiet life, indulging in simple pleasures such as his fondness for tea. He can be seen in town from time to time. Increasingly, he influences things from behind the scenes, but only when necessary, letting younger moths make day-to-day decisions and handle the more energetic work about the village.