Shal-Morzinn was a closed and xenophobic empire far to the west of Seven Cities and southwest of Nemil, which had been ruled by three sorcerer kings known as The Three for the last thousand years. As an empire they had proven quite formidable and were known for annihilating any strangers to their land as a matter of course. The Three despised outsiders and they traded with no-one. Luckily for surrounding nations, they were not expansionist. Few in the Malazan Empire knew of their existence.
Shal-Morzinn filled the lungs of their dead with oil before cremation. This caused the chest to burst, allowing the soul to flee the body.
In The Bonehunters
Fist Rythe Bude, who was an exile from Shal-Morzinn, explained to Ganoes Paran how she had fled her homeland after crossing the Three. She was surprised he had heard of it, although Paran remembered only seeing its name on a Malazan map. She also recounted how Emperor Kellanved and Dancer had once travelled to Shal-Morzinn aboard the imperial flagship, the Twist. The Three were given pause by the pair's ship alone, but afterwards the empire remained as cut off as ever.
Rather than engage the Shal-Morzinn on their home territory, the Bonehunters used a magical gate summoned by the Grey Helms to avoid sailing through their waters completely, using the treacherous, but navigable seas of the realm of Fanderay and Togg.
In Reaper's Gale
The Third Edur Imperial Fleet menaced the waters of the Seven Cities continent searching for champions to face Emperor Rhulad Sengar and capturing natives they thought might provide valuable intelligence. Among those they took back to Letheras with them were four copper-skinned warriors of Shal-Morzinn they dragged from a floundering carrack.
In Dust of Dreams
Upon rising from dust on the Letherii continent, Rystalle Ev recalled that the Orshayn T'lan Imass had been nearly obliterated in a conflict "half a world away." The remaining Orshayn fled the Spires and the enemy in that war, the Order of the Red Sash. This Order was said to be ruled by three powerful mages, probably a reference to Shal-Morzinn.