Bat'leth

The bat'leth was a type of bladed weapon wielded by the Klingons in the parallel universe of the United Federation of Planets. They were retained even after the Klingon race had been converted by the Cybermen in an alternate timeline, with Cybermen being seen to wield them in the First City of Qo'noS. (COMIC: Assimilation²)

Behind the scenes
Though it is not seen within Assimilation² proper, a bat'leth is possessed by Worf. Indeed, he can be seen wielding it on the cover of issue 8.

J. K. Woodward, who worked on the Star Trek crossover Assimilation², released a piece depicting River Song dressed as a Klingon holding a bat'leth.