The long, slender two-handed sword carried by the Romulan warrior nuns of the Qowat Milat and by Elnor, the boy they raised, who uses it with lethal speed.
The tan qalanq is the traditional blade of the Qowat Milat, the order of Romulan warrior nuns settled on the refugee world Vashti. It is a long straight sword with a narrow blade, worn on the back and drawn in a single motion.
In the Picard episode Absolute Candor, Elnor binds himself to Picard's cause and at once uses his sword to behead a former Romulan senator who has drawn a weapon on Picard, after first warning him to choose to live.
Elnor carries the sword through the rest of the first season, fighting Zhat Vash agents at Stardust City and defending Seven of Nine and the reclaimed Borg aboard the Artifact. Picard reproaches him for killing so readily.