Research in the Delta Quadrant facilities was focused on enhancing dragon physiology and perfecting control methods. To monitor and "cultivate" selected specimens, dragons were brought in from Meracydia and placed in paddocks which replicated the environment of the southern continent.
— In-game description
To the untrained ear, one would think that this paddock was named by the dragons enslaved there. However this is false; Eorzean linguists have confirmed there is no actual meaning fur the words "Esh Thom" in the dragon language. As the Allagans considered dragons a lesser race, scholars surmise that the name is somehow intended to mock the Meracydians' heritage.
Home to Tiamat, great wyrm of Midgardsormr's first brood, who fell to and was imprisoned by the Allagans. Even now, she laments her fateful decision to resurrect her beloved brood-brother Bahumut as a primal to aid her in her struggle.