DRAGONKIN SETTLEMENTS
Rimmington:
Built by Kerapac, early/pre 1st Age as a subterranean laboratory, expanded in later 1st Age with a flooded lower chamber to store large wyrm/QBD.
Brimhaven (Sketherin Arakken):
Built by Dactyl, 1st Age, in order to serve as main base/breeding centre for research into dragons.
These are the earliest known Kin settlements, and display the advanced technology of the race. Rimmington is built with a complex series of aqueducts and culverts channeling seawater to and from the QBD's cooling chamber, while the multilevel dungeon is filled with magical seals and hidden 'genetic' laboratories used for Kerapac's earliest experiments. Brimhaven utilizes the natural heat of the volcano, channeling lava into large amphitheatres used to incubate eggs, and also features a cooling drainage system.
First Age settlements were underground, and located far east of any Guthixian/Serenist development. They appeared to avoid the lower races, and move further east as time went on and society spread.
Dragontooth Isle:
Resource dungeon built by Kerapac, likely 1st Age, in order to store a particular group of failed creations, the Celestial Dragons.
Wilderness Cavern (Ullergrax Arakken):
Possibly pre-existing cave, used by at least one Dactyl for experiments on green dragons, likely 1st Age.
Built and utilized within the same 100 year period that saw the rise of Brimhaven, these are likely just a few of many temporary satellite research centres spread throughout the uninhabited east, in order to study, develop, and experiment on new varieties of dragon.