The party first hears the name Ras Nsi during their ascent of Mbala. A traveler lays crushed and dying along the switchbacks, and offers these dying words: “and the meat shows mercy to the butcher… Unto you I grant this mercy, do not trust Ras Nsi.”
According to Saja N’baza, Ras Nsi is ancient. He was chosen by Ubtao to be one of the first barae when Ubtao founded his holy city of Mezro thousands of years ago. In addition to immortality and a number of other powers, Ubtao granted Ras Nsi the ability to command undead. Ras Nsi used this power to raise an army of undead to defend Mezro against the Eshowe and their shadow giant, Eshowdow. Mezro was nearly destroyed, and the other barae all perished in its defense, but ultimately, Mezro defeated Eshowdow and repelled the Eshowe. Unsatisfied with this pyrrhic victory, Ras Nsi led his army to hunt down the remaining Eshowe and eradicated them. After his merciless campaign, Ras Nsi was no longer welcome in Mezro, though he remained steadfast in his dedication to the city’s defense.
Many centuries later, Ras Nsi joined forces with Artus Cimber to defend Mezro from a teeming host of goblins. At their fore stood Artus Cimber’s lifelong enemy and rival seeker of the Ring of Winter. With Artus Cimber’s help, Ras Nsi defeated the goblins and saved Mezro once more. Once Ras Nsi realized he would not be welcomed back to Mezro as the savior he believed himself to be, he set a plan in motion to claim Mezro for himself–as its one, true defender. As his relentless army of undead closed in on Mezro, the Blue Flame of the Spellplague erupted and scoured Mezro from the face of Chult. Ras Nsi’s holy city lay before him in ruins.
In Saja N’baza’s vision, Ras Nsi has since allied himself with the yuan-ti in the lost city of Omu, where the source of the death curse lies. The former bara once swore to protect the holy Chultan city of Mezro, but now he schemes with the yuan-ti to bring Dendar the Night Serpent, Ubtao’s primordial foe, back to Chult to devour the world. Perhaps he was driven mad by the apparent destruction of Mezro during the Spellplague. Whatever Ras Nsi’s motivations are, Saja N’baza insists that he must be stopped.
To the surprise of Artus Cimber, Saja N’baza claims that Mezro has not been destroyed. In fact, Mezro disappeared during the Spellplague to escape Ras Nsi’s army of the undead. According to the oracle’s visions, Mezro can return to Chult only once Ras Nsi has been defeated. Then, and only then, can Artus be reunited with his wife, Alisanda Rayburton.