Ages ago when the drow split from the other elven races, the udodrow fled underground and founded Menzoberranzan. The aevendrow fled far north (to the north pole, basically) and the lorendrow to the far south in Chult. Turns out the magical energy of the underdark, the faezress, not only grants the udodrow their spell-like abilities, but weakens the barriers between the mortal world and the Abyss . . . hence the Menzoberranzan drow's embrace of Lolth and subsequent corruption. Ditto for the duergar dwarves.
We haven't met the lorendrow yet, although they are revealed to exist to the far south in Chult. The aevendrow founded the city of Callidae, the starlight enclave of the novel's title, in the ice caverns of a glacier. The glacier houses the spirit of a powerful elemental of air, a vaati named Qadeej (a Windduke of Aaqa), and the city is kept inhabitable by a warm spring originating from magical (heated) crystal caverns in the underdark below. Some of the caverns are fully enclosed, others are partially open to the sky. The city is so far north, it essentially has six months of daylight, and six months of night-time, with beautiful auroras visible during the night season. As the change between day and night approaches, magic becomes weaker and stops working altogether until the season switches over (this causes major problems for our heroes).
The city of Callidae is mostly inhabited by aevendrow, of course, but also houses decent numbers of ulutiun humans, inugaakalikurit dwarves (or kurit for short, heh), arktos orcs, and a few eladrin, all living in harmony. The aevendrow regularly rescue other peoples from the harsh environment outside Callidae and invite them to live within the city. However, the aevendrow are very paranoid about knowledge of Callidae making its way south to Faerun, and so erase the memories of any visitors who return back to the southern lands.
The aevendrow speak an archaic dialect of the drow language, including drow hand-sign. They do not have the spell-like abilities of the udodrow of the underdark, but have developed a very magical society with advanced spells that create delicious food and powerful healing (apparently, most spell-created foodstuffs in the south are bland and unappetizing). The aevendrow do not hunt or kill livestock for meat, but rather magically conjure meat to supplement their diets. They farm spiders for silk, hagfish for mucus, and muskoxen for . . . I forget. They make amazing clothing out of these resources to protect themselves from the cold, somewhat equivalent to the superior clothing made by drow and surface elves alike. They mine incredibly hard ice from within the glacier that is as hard and permanent as stone, and use it as building material and to forge weapons.
Callidae society is obsessed with a seasonal sports game called cazzcalci, which is a brutal game reminiscent of hockey dialed up to 11. They play once per year as the season switches from day to night, and practice all year in the lead up. The practice keeps them in shape as warriors, to fight their enemies the frost giants, and more recently, the slaadi. They have clerics and paladins, but very little details of their religious beliefs were detailed in the novel, none really.
