Once the chosen weapon of Giancarlo Vespa, he handed it down to Johannes Kal on his death bed. The original version of the sword was damaged when breaking into the Temple of the Five but Johannes reclaimed a future version of the sword from the Darkest Timeline - the damaged original is now in the hands of Ameera Kal (DT).
It's unknown where Giancarlo originally acquired the sword but it bears the makers mark of the Cadarn smithy.
The fey known as Mwgyn referred to this weapon as "The Wasp's Sting" but whether that has any further relevance is unknown.