Blessed Qiraji Pugio

Blessed Qiraji Pugio is a one-handed dagger obtained by turning in Imperial Qiraji Armaments and 3 Elementium Ingots to Arygos within the Temple of Ahn'Qiraj. This dagger is one of four rewards to choose from.

Source
The dagger is a reward from the quest which starts with Arygos in the Temple of Ahn'Qiraj in Silithus.